From 742c42a8bb3714175d41fa30b8914bcbee4b4873 Mon Sep 17 00:00:00 2001
From: Kwame Efah <37164746+efahk@users.noreply.github.com>
Date: Mon, 24 Aug 2026 17:38:05 +0000
Subject: [PATCH 1/7] Implement semver and date custom ops for flags runtime
 props

---
 package-lock.json                             |   9 +-
 .../mixpanel/lib/flags/custom_operators.js    | 129 +++++++++
 packages/mixpanel/lib/flags/local_flags.js    |   1 +
 packages/mixpanel/package.json                |   1 +
 .../mixpanel/test/flags/custom_operators.js   | 274 ++++++++++++++++++
 packages/mixpanel/test/flags/local_flags.js   |  56 ++++
 6 files changed, 469 insertions(+), 1 deletion(-)
 create mode 100644 packages/mixpanel/lib/flags/custom_operators.js
 create mode 100644 packages/mixpanel/test/flags/custom_operators.js

diff --git a/package-lock.json b/package-lock.json
index ba1e49e..746f256 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1060,6 +1060,12 @@
         "node": ">=18"
       }
     },
+    "node_modules/compare-versions": {
+      "version": "6.1.1",
+      "resolved": "https://registry.npmjs.org/compare-versions/-/compare-versions-6.1.1.tgz",
+      "integrity": "sha512-4hm4VPpIecmlg59CHXnRDnqGplJFrbLG4aFEl5vl6cK1u76ws3LLvX7ikFnTDl5vo39sjWD6AaDPYodJp/NNHg==",
+      "license": "MIT"
+    },
     "node_modules/convert-source-map": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-2.0.0.tgz",
@@ -2242,6 +2248,7 @@
       "version": "0.23.0",
       "license": "MIT",
       "dependencies": {
+        "compare-versions": "6.1.1",
         "https-proxy-agent": "7.0.6",
         "json-logic-js": "2.0.5"
       },
@@ -2255,7 +2262,7 @@
     },
     "packages/openfeature-server-provider": {
       "name": "@mixpanel/openfeature-server-provider",
-      "version": "0.1.0",
+      "version": "0.2.0",
       "license": "MIT",
       "devDependencies": {
         "@openfeature/core": "^1.9.2",
diff --git a/packages/mixpanel/lib/flags/custom_operators.js b/packages/mixpanel/lib/flags/custom_operators.js
new file mode 100644
index 0000000..023bfc3
--- /dev/null
+++ b/packages/mixpanel/lib/flags/custom_operators.js
@@ -0,0 +1,129 @@
+const jsonLogic = require("json-logic-js");
+const { compareVersions } = require("compare-versions");
+
+// Strict RFC3339 guard for datetime strings.
+const RFC3339_PATTERN =
+  /^\d{4}-\d{2}-\d{2}[Tt]\d{2}:\d{2}:\d{2}(\.\d+)?([Zz]|[+-]\d{2}:\d{2})$/;
+
+// SemVer 2.0.0 requires major.minor.patch; partial versions are zero-padded to this.
+const SEMVER_PARTS = 3;
+
+// Epoch milliseconds are compared as int64 elsewhere, so anything at or beyond this is out of range.
+const MAX_EPOCH_MS = 9223372036854775808;
+
+// Using the official semantic versioning 2.0.0 regular expression to handle cross-platform validation
+// differences on other SDK's. For example, some platforms allow leading zeros even though it is not valid
+// as part of the Semver 2.0.0 spec. See https://semver.org/
+const SEMVER_PATTERN =
+  /^(0|[1-9]\d*)\.(0|[1-9]\d*)\.(0|[1-9]\d*)(?:-((?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*)(?:\.(?:0|[1-9]\d*|\d*[a-zA-Z-][0-9a-zA-Z-]*))*))?(?:\+([0-9a-zA-Z-]+(?:\.[0-9a-zA-Z-]+)*))?$/;
+
+jsonLogic.add_operation("semver_compare", semverCompare);
+jsonLogic.add_operation("datetime_compare", datetimeCompare);
+
+// Implements a custom operation for semantic versioning comparison that conforms to the semver 2.0.0 standard.
+// Prior to comparison, any leading version prefix is stripped.
+function semverCompare(actual, symbol, target) {
+  if (arguments.length !== 3) {
+    return false;
+  }
+  if (typeof actual !== "string" || typeof target !== "string") {
+    return false;
+  }
+  const actualVersion = normalizeSemver(actual);
+  const targetVersion = normalizeSemver(target);
+  if (!SEMVER_PATTERN.test(actualVersion) || !SEMVER_PATTERN.test(targetVersion)) {
+    return false;
+  }
+  const cmp = compareVersions(actualVersion, targetVersion);
+  return comparatorMatches(cmp, symbol);
+}
+
+// Implements a custom operation for datetime comparison.
+// The target value stored on the feature flag is the millisecond epoch, whereas the actual value provided at evaluation time must be RFC-3339 formatted.
+function datetimeCompare(actual, symbol, target) {
+  if (arguments.length !== 3) {
+    return false;
+  }
+  const actualSec = convertRfc3339ToUnixSeconds(actual);
+  const targetSec = convertUnixMillisecondsToSeconds(target);
+  if (actualSec === null || targetSec === null) {
+    return false;
+  }
+  const cmp = actualSec - targetSec;
+  return comparatorMatches(cmp, symbol);
+}
+
+function comparatorMatches(cmp, symbol) {
+  switch (symbol) {
+    case "=":
+      return cmp === 0;
+    case "!=":
+      return cmp !== 0;
+    case "<":
+      return cmp < 0;
+    case "<=":
+      return cmp <= 0;
+    case ">":
+      return cmp > 0;
+    case ">=":
+      return cmp >= 0;
+    default:
+      return false;
+  }
+}
+
+function normalizeSemver(version) {
+  const stripped = version.trim().replace(/^[vV]/, "");
+
+  let suffixStart = stripped.length;
+  for (const separator of ["-", "+"]) {
+    const index = stripped.indexOf(separator);
+    if (index !== -1 && index < suffixStart) {
+      suffixStart = index;
+    }
+  }
+
+  const core = stripped.slice(0, suffixStart);
+  const suffix = stripped.slice(suffixStart);
+
+  const parts = core.split(".");
+  while (parts.length < SEMVER_PARTS) {
+    parts.push("0");
+  }
+  return parts.join(".") + suffix;
+}
+
+function convertRfc3339ToUnixSeconds(value) {
+  if (typeof value !== "string") {
+    return null;
+  }
+  const normalized = value.trim().toUpperCase();
+  if (!RFC3339_PATTERN.test(normalized)) {
+    return null;
+  }
+  const ms = Date.parse(normalized);
+  if (Number.isNaN(ms)) {
+    return null;
+  }
+  return Math.floor(ms / 1000);
+}
+
+function convertUnixMillisecondsToSeconds(value) {
+  if (typeof value !== "number" || !Number.isFinite(value)) {
+    return null;
+  }
+  // A value int64 cannot represent is not a real timestamp; treating one as a bound would let a
+  // nonsense target define a rollout window.
+  if (value >= MAX_EPOCH_MS || value <= -MAX_EPOCH_MS) {
+    return null;
+  }
+  return Math.trunc(value / 1000);
+}
+
+module.exports = {
+  comparatorMatches,
+  semverCompare,
+  convertRfc3339ToUnixSeconds,
+  convertUnixMillisecondsToSeconds,
+  datetimeCompare,
+};
diff --git a/packages/mixpanel/lib/flags/local_flags.js b/packages/mixpanel/lib/flags/local_flags.js
index fc834ef..15bd81d 100644
--- a/packages/mixpanel/lib/flags/local_flags.js
+++ b/packages/mixpanel/lib/flags/local_flags.js
@@ -24,6 +24,7 @@ const {
   asFallback,
 } = require("./variant_source");
 const { apply } = require("json-logic-js");
+require("./custom_operators");
 
 class LocalFeatureFlagsProvider extends FeatureFlagsProvider {
   /**
diff --git a/packages/mixpanel/package.json b/packages/mixpanel/package.json
index 39b7d60..46057c4 100644
--- a/packages/mixpanel/package.json
+++ b/packages/mixpanel/package.json
@@ -35,6 +35,7 @@
     "build": "tsc --build"
   },
   "dependencies": {
+    "compare-versions": "6.1.1",
     "https-proxy-agent": "7.0.6",
     "json-logic-js": "2.0.5"
   },
diff --git a/packages/mixpanel/test/flags/custom_operators.js b/packages/mixpanel/test/flags/custom_operators.js
new file mode 100644
index 0000000..ac4607a
--- /dev/null
+++ b/packages/mixpanel/test/flags/custom_operators.js
@@ -0,0 +1,274 @@
+const { apply } = require("json-logic-js");
+// Requiring the module registers semver_compare and datetime_compare on the shared
+// json-logic-js instance used by apply().
+require("../../lib/flags/custom_operators");
+
+const varNode = (key) => ({ var: key });
+
+const semverRule = (key, sym, target) => ({
+  semver_compare: [varNode(key), sym, target],
+});
+
+const datetimeRule = (key, sym, target) => ({
+  datetime_compare: [varNode(key), sym, target],
+});
+
+const customBetween = (op, key, lo, hi) => ({
+  and: [
+    { [op]: [varNode(key), ">=", lo] },
+    { [op]: [varNode(key), "<=", hi] },
+  ],
+});
+
+const datetimeBetween = (key, lo, hi) => ({
+  and: [
+    { datetime_compare: [varNode(key), ">=", lo] },
+    { datetime_compare: [varNode(key), "<=", hi] },
+  ],
+});
+
+// Epoch-millisecond constants (UTC instants) used as datetime targets, matching the UI format.
+const JUL16_MS = 1_784_160_000_000; // 2026-07-16T00:00:00Z
+const JAN1_MS = 1_767_225_600_000; // 2026-01-01T00:00:00Z
+const DEC31_MS = 1_798_675_200_000; // 2026-12-31T00:00:00Z
+const JUL16_END_MS = 1_784_246_399_999; // 2026-07-16T23:59:59.999Z
+const LEAP_DAY_MS = 1_709_164_800_000; // 2024-02-29T00:00:00Z
+const JUL16_INDIA_MS = 1_784_140_200_000; // 2026-07-16T00:00:00+05:30
+const JUL16_PACIFIC_MS = 1_784_188_800_000; // 2026-07-16T00:00:00-08:00
+
+describe("semver_compare operator", () => {
+  it.each([
+    ["is, equal", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3" }, true],
+    ["is, not equal", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.4" }, false],
+    ["is not", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.4" }, true],
+    ["less than, patch", semverRule("app_version", "<", "1.2.3"), { app_version: "1.2.2" }, true],
+    ["less than, false", semverRule("app_version", "<", "1.2.3"), { app_version: "1.2.3" }, false],
+    ["less or equal, boundary", semverRule("app_version", "<=", "1.2.3"), { app_version: "1.2.3" }, true],
+    ["greater than, minor", semverRule("app_version", ">", "1.2.3"), { app_version: "1.3.0" }, true],
+    ["greater or equal, boundary", semverRule("app_version", ">=", "1.2.3"), { app_version: "1.2.3" }, true],
+    ["double-digit ordering (not lexical)", semverRule("app_version", ">", "1.9.0"), { app_version: "1.10.0" }, true],
+    ["prerelease precedes release", semverRule("app_version", "<", "1.0.0"), { app_version: "1.0.0-alpha" }, true],
+    ["lenient v-prefix", semverRule("app_version", "=", "1.2.3"), { app_version: "v1.2.3" }, true],
+    ["lenient uppercase V-prefix", semverRule("app_version", "=", "1.2.3"), { app_version: "V1.2.3" }, true],
+    ["v-prefix keeps prerelease", semverRule("app_version", "<", "1.0.0"), { app_version: "v1.0.0-alpha" }, true],
+    ["v-prefix, not equal", semverRule("app_version", "!=", "1.2.3"), { app_version: "v1.2.4" }, true],
+    ["v-prefix, at or below", semverRule("app_version", "<=", "1.2.3"), { app_version: "v1.2.3" }, true],
+    ["v-prefix, greater", semverRule("app_version", ">", "1.2.3"), { app_version: "v1.2.4" }, true],
+    ["v-prefix, at or above", semverRule("app_version", ">=", "1.2.3"), { app_version: "v1.2.3" }, true],
+    ["lenient minor-only target", semverRule("app_version", "=", "1.2"), { app_version: "1.2.0" }, true],
+    // Every symbol is asserted in both directions.
+    ["is not, equal", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3" }, false],
+    ["less or equal, above", semverRule("app_version", "<=", "1.2.3"), { app_version: "1.2.4" }, false],
+    ["greater than, below", semverRule("app_version", ">", "1.2.3"), { app_version: "1.2.2" }, false],
+    ["greater or equal, below", semverRule("app_version", ">=", "1.2.3"), { app_version: "1.2.2" }, false],
+    // Prerelease precedence, SemVer 2.0.0 section 11.
+    ["prerelease alpha before beta", semverRule("app_version", "<", "1.0.0-beta"), { app_version: "1.0.0-alpha" }, true],
+    ["prerelease beta before rc1", semverRule("app_version", "<", "1.0.0-rc1"), { app_version: "1.0.0-beta" }, true],
+    ["prerelease rc1 before rc2", semverRule("app_version", "<", "1.0.0-rc2"), { app_version: "1.0.0-rc1" }, true],
+    ["more prerelease fields wins", semverRule("app_version", "<", "1.0.0-alpha.1"), { app_version: "1.0.0-alpha" }, true],
+    ["numeric identifier below alphanumeric", semverRule("app_version", "<", "1.0.0-alpha.beta"), { app_version: "1.0.0-alpha.1" }, true],
+    ["fewer fields below alphanumeric", semverRule("app_version", "<", "1.0.0-alpha.beta"), { app_version: "1.0.0-alpha" }, true],
+    ["numeric identifiers compare numerically", semverRule("app_version", "<", "1.0.0-beta.11"), { app_version: "1.0.0-beta.2" }, true],
+    ["dotted identifier ordering, letters", semverRule("app_version", "<", "1.0.0-b.1"), { app_version: "1.0.0-a.1" }, true],
+    ["dotted identifier ordering, digits", semverRule("app_version", "<", "1.0.0-a.2"), { app_version: "1.0.0-a.1" }, true],
+    ["identical prereleases are equal", semverRule("app_version", "=", "1.0.0-rc1"), { app_version: "1.0.0-rc1" }, true],
+    ["rc1 outranks dotted rc.1", semverRule("app_version", ">", "1.0.0-rc.1"), { app_version: "1.0.0-rc1" }, true],
+    ["core version dominates prerelease", semverRule("app_version", ">", "1.9.9"), { app_version: "2.0.0-alpha" }, true],
+    // A release outranks its own prerelease, asserted from both sides and under every symbol.
+    ["release outranks its prerelease", semverRule("app_version", ">", "1.0.0-alpha"), { app_version: "1.0.0" }, true],
+    ["release at or above its prerelease", semverRule("app_version", ">=", "1.0.0-rc1"), { app_version: "1.0.0" }, true],
+    ["release differs from its prerelease", semverRule("app_version", "!=", "1.0.0-alpha"), { app_version: "1.0.0" }, true],
+    ["prerelease differs from its release", semverRule("app_version", "!=", "1.0.0"), { app_version: "1.0.0-alpha" }, true],
+    ["prerelease at or below its release", semverRule("app_version", "<=", "1.0.0"), { app_version: "1.0.0-alpha" }, true],
+    ["prerelease of a higher core still wins", semverRule("app_version", ">", "0.9.9"), { app_version: "1.0.0-alpha" }, true],
+    ["prerelease below the next patch", semverRule("app_version", "<", "1.0.1"), { app_version: "1.0.0-rc1" }, true],
+    // Prerelease identifier comparison, SemVer 2.0.0 section 11.4.
+    ["numeric identifiers are not compared lexically", semverRule("app_version", "<", "1.0.0-10"), { app_version: "1.0.0-2" }, true],
+    ["numeric identifier ranks below alphanumeric", semverRule("app_version", "<", "1.0.0-alpha"), { app_version: "1.0.0-1" }, true],
+    ["hyphen inside an identifier sorts by ascii", semverRule("app_version", "<", "1.0.0-alpha-1"), { app_version: "1.0.0-alpha" }, true],
+    ["beta ranks below rc", semverRule("app_version", "<", "1.0.0-rc.1"), { app_version: "1.0.0-beta.11" }, true],
+    ["last prerelease ranks below the release", semverRule("app_version", "<", "1.0.0"), { app_version: "1.0.0-rc.1" }, true],
+    // Build metadata carries no precedence.
+    ["build metadata ignored", semverRule("app_version", "=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, true],
+    ["build metadata ignored with prerelease", semverRule("app_version", "=", "1.0.0-alpha"), { app_version: "1.0.0-alpha+build" }, true],
+    ["build metadata with hyphen ignored", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3+build.1-2" }, true],
+    // Ignored means equal, so every symbol has to agree with that.
+    ["build metadata leaves versions equal", semverRule("app_version", "!=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, false],
+    ["build metadata is not less", semverRule("app_version", "<", "1.0.0+build2"), { app_version: "1.0.0+build1" }, false],
+    ["build metadata is not greater", semverRule("app_version", ">", "1.0.0+build2"), { app_version: "1.0.0+build1" }, false],
+    ["build metadata at or below", semverRule("app_version", "<=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, true],
+    ["build metadata at or above", semverRule("app_version", ">=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, true],
+    ["build metadata does not block ordering", semverRule("app_version", "<", "1.0.1+build1"), { app_version: "1.0.0+build9" }, true],
+    ["build metadata does not block reverse ordering", semverRule("app_version", ">", "1.0.0+build9"), { app_version: "1.0.1+build1" }, true],
+    // Partial versions keep their prerelease once zero-padded.
+    ["partial version with prerelease", semverRule("app_version", "=", "1.2.0-alpha"), { app_version: "1.2-alpha" }, true],
+    ["partial prerelease below later minor", semverRule("app_version", "<", "1.3.1"), { app_version: "1.2-alpha" }, true],
+    ["partial prerelease below its release", semverRule("app_version", "<", "1.2.0"), { app_version: "1.2-alpha" }, true],
+    ["major-only with prerelease", semverRule("app_version", "<", "1.0.0"), { app_version: "1-rc1" }, true],
+    // An empty prerelease is invalid, so it is rejected rather than treated as the bare release.
+    ["empty prerelease, no match", semverRule("app_version", "=", "1.0.0"), { app_version: "1.0.0-" }, false],
+    ["empty prerelease, not-equal also false", semverRule("app_version", "!=", "1.0.0"), { app_version: "1.0.0-" }, false],
+    ["empty prerelease on partial version, no match", semverRule("app_version", "=", "1.2.0"), { app_version: "1.2-" }, false],
+    ["empty prerelease on partial version, not-equal also false", semverRule("app_version", "!=", "1.2.0"), { app_version: "1.2-" }, false],
+    // Hyphens are legal inside a prerelease identifier, so these are NOT empty prereleases.
+    ["trailing hyphen inside identifier", semverRule("app_version", "<", "1.0.0"), { app_version: "1.0.0-alpha-" }, true],
+    // SemVer 2.0.0 forbids leading zeros in the core, so these are rejected rather than normalized.
+    ["leading zero in major, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "01.2.3" }, false],
+    ["leading zero in major, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "01.2.3" }, false],
+    ["leading zero in minor, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.02.3" }, false],
+    ["leading zero in minor, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.02.3" }, false],
+    ["leading zero in patch, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.03" }, false],
+    ["leading zero in patch, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.03" }, false],
+    ["leading zeros throughout, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "01.02.03" }, false],
+    ["leading zeros throughout, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "01.02.03" }, false],
+    // A numeric prerelease identifier may not carry a leading zero either (section 9).
+    ["numeric prerelease with leading zero, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-01" }, false],
+    ["numeric prerelease with leading zero, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-01" }, false],
+    ["dotted numeric prerelease with leading zero, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-rc.01" }, false],
+    ["dotted numeric prerelease with leading zero, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-rc.01" }, false],
+    // An alphanumeric identifier may contain digits, so this one stays valid.
+    ["alphanumeric prerelease with digits", semverRule("app_version", "<", "1.2.3"), { app_version: "1.2.3-rc01" }, true],
+    ["between, inside", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.5.0" }, true],
+    ["between, low boundary inclusive", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.2.3" }, true],
+    ["between, high boundary inclusive", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "2.0.0" }, true],
+    ["between, below", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.0.0" }, false],
+    ["between, above", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "2.0.1" }, false],
+    // A prerelease sits below its own release, which decides both boundary cases.
+    ["between, prerelease inside", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.5.0-rc1" }, true],
+    ["between, prerelease below the high bound", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "2.0.0-rc1" }, true],
+    ["between, prerelease of the low bound falls out", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.2.3-rc1" }, false],
+    ["between, invalid version", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "not-a-version" }, false],
+    ["between, single-point range", customBetween("semver_compare", "app_version", "1.2.3", "1.2.3"), { app_version: "1.2.3" }, true],
+    // Fail-closed: unparseable or missing values never match.
+    ["invalid actual, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "not-a-version" }, false],
+    ["non-string actual, no match", semverRule("app_version", "=", "1.2.3"), { app_version: 123 }, false],
+    ["missing property, no match", semverRule("app_version", "=", "1.2.3"), {}, false],
+    // A malformed version must never be padded or coerced into a real one. Both symbols are
+    // asserted so that "accepted at all" is observable rather than masked by a single false.
+    ["empty version, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "" }, false],
+    ["empty version, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "" }, false],
+    ["bare v, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "v" }, false],
+    ["bare v, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "v" }, false],
+    ["leading separator, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "-1.2.3" }, false],
+    ["leading separator, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "-1.2.3" }, false],
+    ["trailing dot, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1." }, false],
+    ["trailing dot, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1." }, false],
+    ["trailing dot after patch, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3." }, false],
+    ["trailing dot after patch, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3." }, false],
+    ["empty middle segment, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1..2" }, false],
+    ["empty middle segment, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1..2" }, false],
+    ["four components, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3.4" }, false],
+    ["four components, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3.4" }, false],
+    ["range prefix, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "^1.2.3" }, false],
+    ["range prefix, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "^1.2.3" }, false],
+    ["version inside text, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "abc1.2.3" }, false],
+    ["version inside text, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "abc1.2.3" }, false],
+    ["empty build metadata, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3+" }, false],
+    ["empty build metadata, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3+" }, false],
+    ["empty prerelease identifier, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-alpha..1" }, false],
+    ["empty prerelease identifier, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-alpha..1" }, false],
+    ["lone dot prerelease, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-." }, false],
+    ["lone dot prerelease, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-." }, false],
+    ["underscore in prerelease, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-ALPHA_BETA" }, false],
+    ["underscore in prerelease, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-ALPHA_BETA" }, false],
+    ["doubled v-prefix, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "vv1.2.3" }, false],
+    ["doubled v-prefix, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "vv1.2.3" }, false],
+    ["missing operand, no match", { semver_compare: [varNode("app_version"), "="] }, { app_version: "1.2.3" }, false],
+  ])("%s", (_name, rule, data, want) => {
+    expect(apply(rule, data)).toBe(want);
+  });
+});
+
+describe("datetime_compare operator", () => {
+  it.each([
+    // Asymmetric contract: subject (runtime var) is a strict RFC3339 string, target is epoch ms.
+    ["before, true", datetimeRule("signup", "<", JUL16_MS), { signup: "2026-07-15T00:00:00Z" }, true],
+    ["before, false", datetimeRule("signup", "<", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, false],
+    ["on (equal), true", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, true],
+    ["not on, true", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, true],
+    ["since (>=), boundary", datetimeRule("signup", ">=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, true],
+    ["after (>), true", datetimeRule("signup", ">", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, true],
+    ["after (>), false", datetimeRule("signup", ">", JUL16_MS), { signup: "2026-07-15T00:00:00Z" }, false],
+    // Every symbol is asserted in both directions.
+    ["at or before, boundary", datetimeRule("signup", "<=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, true],
+    ["at or before, after", datetimeRule("signup", "<=", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, false],
+    ["on (equal), false", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, false],
+    ["not on, equal", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, false],
+    ["since (>=), before", datetimeRule("signup", ">=", JUL16_MS), { signup: "2026-07-15T00:00:00Z" }, false],
+    ["between, inside", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2026-06-15T00:00:00Z" }, true],
+    ["between, low boundary inclusive", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2026-01-01T00:00:00Z" }, true],
+    ["between, high boundary inclusive", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2026-12-31T00:00:00Z" }, true],
+    ["between, before range", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2025-12-31T00:00:00Z" }, false],
+    ["between, after range", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2027-01-01T00:00:00Z" }, false],
+    // A leap day is a real date.
+    ["leap day", datetimeRule("signup", "=", LEAP_DAY_MS), { signup: "2024-02-29T00:00:00Z" }, true],
+    // Time-zone offsets change the instant.
+    ["offset with half-hour minutes", datetimeRule("signup", "=", JUL16_INDIA_MS), { signup: "2026-07-16T00:00:00+05:30" }, true],
+    ["rfc3339 subject with offset", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T02:00:00+02:00" }, true],
+    ["positive offset precedes utc midnight", datetimeRule("signup", "<", JUL16_MS), { signup: "2026-07-16T00:00:00+05:30" }, true],
+    ["negative offset", datetimeRule("signup", "=", JUL16_PACIFIC_MS), { signup: "2026-07-16T00:00:00-08:00" }, true],
+    ["negative offset follows utc midnight", datetimeRule("signup", ">", JUL16_MS), { signup: "2026-07-16T00:00:00-08:00" }, true],
+    ["zero offset equals Z", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00+00:00" }, true],
+    // Sub-second precision is dropped, on both sides. The end-of-day rows are the window the UI
+    // emits for a single date, whose upper bound carries .999.
+    ["one-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.5Z" }, true],
+    ["three-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.500Z" }, true],
+    ["six-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.123456Z" }, true],
+    ["nine-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.999999999Z" }, true],
+    ["zero fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.0Z" }, true],
+    ["fractional seconds truncated", datetimeRule("signup", ">=", JUL16_MS), { signup: "2026-07-16T00:00:00.500Z" }, true],
+    ["end-of-day target drops its .999", datetimeRule("signup", "=", JUL16_END_MS), { signup: "2026-07-16T23:59:59Z" }, true],
+    ["end-of-day target is an inclusive bound", datetimeRule("signup", "<=", JUL16_END_MS), { signup: "2026-07-16T23:59:59Z" }, true],
+    ["end-of-day, fractional subject too", datetimeRule("signup", "=", JUL16_END_MS), { signup: "2026-07-16T23:59:59.999Z" }, true],
+    ["end-of-day inclusive, fractional subject", datetimeRule("signup", "<=", JUL16_END_MS), { signup: "2026-07-16T23:59:59.999Z" }, true],
+    // Fractional on both sides: the shape the UI actually round-trips.
+    // Trimming and lowercasing.
+    ["lowercased subject with fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16t00:00:00.500z" }, true],
+    ["lowercased subject with offset", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16t02:00:00+02:00" }, true],
+    ["whitespace-padded subject", datetimeRule("signup", "=", JUL16_MS), { signup: " 2026-07-16T00:00:00Z " }, true],
+    ["lowercased rfc3339 subject", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16t00:00:00z" }, true],
+    // Shape violations, asserted under both = and != so that "accepted at all" is observable.
+    // RFC 3339 also permits 24:00:00 as end-of-day. Platforms disagree on it, so no vector
+    // asserts it either way.
+    ["one-digit month, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-7-16T00:00:00Z" }, false],
+    ["one-digit month, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-7-16T00:00:00Z" }, false],
+    ["space separator, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16 00:00:00Z" }, false],
+    ["space separator, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16 00:00:00Z" }, false],
+    ["missing zone, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00" }, false],
+    ["missing zone, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00" }, false],
+    ["empty fraction, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.Z" }, false],
+    ["empty fraction, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00.Z" }, false],
+    ["offset without colon, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00+0200" }, false],
+    ["offset without colon, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00+0200" }, false],
+    ["short offset, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00+02" }, false],
+    ["short offset, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00+02" }, false],
+    ["trailing junk, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00Zextra" }, false],
+    ["trailing junk, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00Zextra" }, false],
+    ["basic format, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "20260716T000000Z" }, false],
+    ["basic format, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "20260716T000000Z" }, false],
+    ["zone after lowercase z, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00z00:00" }, false],
+    ["zone after lowercase z, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00z00:00" }, false],
+    ["comma fractional separator, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00,5Z" }, false],
+    ["comma fractional separator, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00,5Z" }, false],
+    // Fail-closed: subject must be an RFC3339 string, target must be an epoch-ms number.
+    ["numeric subject, no match", datetimeRule("signup", "=", JUL16_MS), { signup: JUL16_MS }, false],
+    ["negative epoch-ms target resolves to -1s", datetimeRule("signup", "=", -1500), { signup: "1969-12-31T23:59:59Z" }, true],
+    ["negative epoch-ms target, not equal", datetimeRule("signup", "!=", -1500), { signup: "1969-12-31T23:59:59Z" }, false],
+    ["negative epoch-ms target, at or after", datetimeRule("signup", ">=", -1500), { signup: "1969-12-31T23:59:59Z" }, true],
+    ["negative epoch-ms target, before", datetimeRule("signup", "<", -1500), { signup: "1969-12-31T23:59:58Z" }, true],
+    ["negative epoch-ms target, after", datetimeRule("signup", ">", -2500), { signup: "1969-12-31T23:59:59Z" }, true],
+    ["subject floors, it does not truncate", datetimeRule("signup", "=", -2000), { signup: "1969-12-31T23:59:58.500Z" }, true],
+    ["subject floors, not to -1s", datetimeRule("signup", "!=", -1000), { signup: "1969-12-31T23:59:58.500Z" }, true],
+    ["target beyond representable range, no match", { datetime_compare: [varNode("signup"), "=", 1e308] }, { signup: "2026-07-16T00:00:00Z" }, false],
+    ["target beyond representable range, greater-than also false", { datetime_compare: [varNode("signup"), ">", 1e308] }, { signup: "2026-07-16T00:00:00Z" }, false],
+    ["target beyond representable range, less-than also false", { datetime_compare: [varNode("signup"), "<", 1e308] }, { signup: "2026-07-16T00:00:00Z" }, false],
+    ["bare date subject, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16" }, false],
+    ["bare date subject, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16" }, false],
+    ["zoneless datetime subject, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00" }, false],
+    ["non-datetime string, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "yesterday" }, false],
+    ["missing property, no match", datetimeRule("signup", "=", JUL16_MS), {}, false],
+    ["missing operand, no match", { datetime_compare: [varNode("signup"), "="] }, { signup: "2026-07-16T00:00:00Z" }, false],
+  ])("%s", (_name, rule, data, want) => {
+    expect(apply(rule, data)).toBe(want);
+  });
+});
diff --git a/packages/mixpanel/test/flags/local_flags.js b/packages/mixpanel/test/flags/local_flags.js
index 312f6fe..2d122af 100644
--- a/packages/mixpanel/test/flags/local_flags.js
+++ b/packages/mixpanel/test/flags/local_flags.js
@@ -517,6 +517,62 @@ describe("LocalFeatureFlagsProvider", () => {
       expect(result.variant_value).toBe(FALLBACK_NAME);
     });
 
+    it("should return variant when semver_compare runtime rule satisfied", async () => {
+      const runtimeEvaluationRule = {
+        semver_compare: [{ var: "app_version" }, ">=", "1.2.3"],
+      };
+      await createFlagAndLoadItIntoSDK({ runtimeEvaluationRule }, provider);
+
+      const context = userContextWithRuntimeParameters({
+        app_version: "1.5.0",
+      });
+
+      const result = provider.getVariant(FLAG_KEY, FALLBACK, context);
+      assertVariantReturned(result);
+    });
+
+    it("should return fallback when semver_compare runtime rule not satisfied", async () => {
+      const runtimeEvaluationRule = {
+        semver_compare: [{ var: "app_version" }, ">=", "1.2.3"],
+      };
+      await createFlagAndLoadItIntoSDK({ runtimeEvaluationRule }, provider);
+
+      const context = userContextWithRuntimeParameters({
+        app_version: "1.0.0",
+      });
+
+      const result = provider.getVariant(FLAG_KEY, FALLBACK, context);
+      expect(result.variant_value).toBe(FALLBACK_NAME);
+    });
+
+    it("should return variant when datetime_compare runtime rule satisfied", async () => {
+      const runtimeEvaluationRule = {
+        datetime_compare: [{ var: "signup" }, "<", 1_784_160_000_000],
+      };
+      await createFlagAndLoadItIntoSDK({ runtimeEvaluationRule }, provider);
+
+      const context = userContextWithRuntimeParameters({
+        signup: "2026-07-15T00:00:00Z",
+      });
+
+      const result = provider.getVariant(FLAG_KEY, FALLBACK, context);
+      assertVariantReturned(result);
+    });
+
+    it("should return fallback when datetime_compare runtime rule not satisfied", async () => {
+      const runtimeEvaluationRule = {
+        datetime_compare: [{ var: "signup" }, "<", 1_784_160_000_000],
+      };
+      await createFlagAndLoadItIntoSDK({ runtimeEvaluationRule }, provider);
+
+      const context = userContextWithRuntimeParameters({
+        signup: "2026-07-17T00:00:00Z",
+      });
+
+      const result = provider.getVariant(FLAG_KEY, FALLBACK, context);
+      expect(result.variant_value).toBe(FALLBACK_NAME);
+    });
+
     it("should respect legacy runtime evaluation when satisfied", async () => {
       const legacyRuntimeRule = { plan: "premium", region: "US" };
       await createFlagAndLoadItIntoSDK(

From 3b6e3ff5f40a2288ec9bdf8dab9923038047ae0b Mon Sep 17 00:00:00 2001
From: Kwame Efah <37164746+efahk@users.noreply.github.com>
Date: Mon, 24 Aug 2026 17:39:32 +0000
Subject: [PATCH 2/7] linting

---
 .../mixpanel/lib/flags/custom_operators.js    |    5 +-
 .../mixpanel/test/flags/custom_operators.js   | 1370 ++++++++++++++---
 2 files changed, 1175 insertions(+), 200 deletions(-)

diff --git a/packages/mixpanel/lib/flags/custom_operators.js b/packages/mixpanel/lib/flags/custom_operators.js
index 023bfc3..ee79042 100644
--- a/packages/mixpanel/lib/flags/custom_operators.js
+++ b/packages/mixpanel/lib/flags/custom_operators.js
@@ -31,7 +31,10 @@ function semverCompare(actual, symbol, target) {
   }
   const actualVersion = normalizeSemver(actual);
   const targetVersion = normalizeSemver(target);
-  if (!SEMVER_PATTERN.test(actualVersion) || !SEMVER_PATTERN.test(targetVersion)) {
+  if (
+    !SEMVER_PATTERN.test(actualVersion) ||
+    !SEMVER_PATTERN.test(targetVersion)
+  ) {
     return false;
   }
   const cmp = compareVersions(actualVersion, targetVersion);
diff --git a/packages/mixpanel/test/flags/custom_operators.js b/packages/mixpanel/test/flags/custom_operators.js
index ac4607a..c0ebbff 100644
--- a/packages/mixpanel/test/flags/custom_operators.js
+++ b/packages/mixpanel/test/flags/custom_operators.js
@@ -14,10 +14,7 @@ const datetimeRule = (key, sym, target) => ({
 });
 
 const customBetween = (op, key, lo, hi) => ({
-  and: [
-    { [op]: [varNode(key), ">=", lo] },
-    { [op]: [varNode(key), "<=", hi] },
-  ],
+  and: [{ [op]: [varNode(key), ">=", lo] }, { [op]: [varNode(key), "<=", hi] }],
 });
 
 const datetimeBetween = (key, lo, hi) => ({
@@ -38,142 +35,742 @@ const JUL16_PACIFIC_MS = 1_784_188_800_000; // 2026-07-16T00:00:00-08:00
 
 describe("semver_compare operator", () => {
   it.each([
-    ["is, equal", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3" }, true],
-    ["is, not equal", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.4" }, false],
-    ["is not", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.4" }, true],
-    ["less than, patch", semverRule("app_version", "<", "1.2.3"), { app_version: "1.2.2" }, true],
-    ["less than, false", semverRule("app_version", "<", "1.2.3"), { app_version: "1.2.3" }, false],
-    ["less or equal, boundary", semverRule("app_version", "<=", "1.2.3"), { app_version: "1.2.3" }, true],
-    ["greater than, minor", semverRule("app_version", ">", "1.2.3"), { app_version: "1.3.0" }, true],
-    ["greater or equal, boundary", semverRule("app_version", ">=", "1.2.3"), { app_version: "1.2.3" }, true],
-    ["double-digit ordering (not lexical)", semverRule("app_version", ">", "1.9.0"), { app_version: "1.10.0" }, true],
-    ["prerelease precedes release", semverRule("app_version", "<", "1.0.0"), { app_version: "1.0.0-alpha" }, true],
-    ["lenient v-prefix", semverRule("app_version", "=", "1.2.3"), { app_version: "v1.2.3" }, true],
-    ["lenient uppercase V-prefix", semverRule("app_version", "=", "1.2.3"), { app_version: "V1.2.3" }, true],
-    ["v-prefix keeps prerelease", semverRule("app_version", "<", "1.0.0"), { app_version: "v1.0.0-alpha" }, true],
-    ["v-prefix, not equal", semverRule("app_version", "!=", "1.2.3"), { app_version: "v1.2.4" }, true],
-    ["v-prefix, at or below", semverRule("app_version", "<=", "1.2.3"), { app_version: "v1.2.3" }, true],
-    ["v-prefix, greater", semverRule("app_version", ">", "1.2.3"), { app_version: "v1.2.4" }, true],
-    ["v-prefix, at or above", semverRule("app_version", ">=", "1.2.3"), { app_version: "v1.2.3" }, true],
-    ["lenient minor-only target", semverRule("app_version", "=", "1.2"), { app_version: "1.2.0" }, true],
+    [
+      "is, equal",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3" },
+      true,
+    ],
+    [
+      "is, not equal",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.4" },
+      false,
+    ],
+    [
+      "is not",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.4" },
+      true,
+    ],
+    [
+      "less than, patch",
+      semverRule("app_version", "<", "1.2.3"),
+      { app_version: "1.2.2" },
+      true,
+    ],
+    [
+      "less than, false",
+      semverRule("app_version", "<", "1.2.3"),
+      { app_version: "1.2.3" },
+      false,
+    ],
+    [
+      "less or equal, boundary",
+      semverRule("app_version", "<=", "1.2.3"),
+      { app_version: "1.2.3" },
+      true,
+    ],
+    [
+      "greater than, minor",
+      semverRule("app_version", ">", "1.2.3"),
+      { app_version: "1.3.0" },
+      true,
+    ],
+    [
+      "greater or equal, boundary",
+      semverRule("app_version", ">=", "1.2.3"),
+      { app_version: "1.2.3" },
+      true,
+    ],
+    [
+      "double-digit ordering (not lexical)",
+      semverRule("app_version", ">", "1.9.0"),
+      { app_version: "1.10.0" },
+      true,
+    ],
+    [
+      "prerelease precedes release",
+      semverRule("app_version", "<", "1.0.0"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "lenient v-prefix",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "v1.2.3" },
+      true,
+    ],
+    [
+      "lenient uppercase V-prefix",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "V1.2.3" },
+      true,
+    ],
+    [
+      "v-prefix keeps prerelease",
+      semverRule("app_version", "<", "1.0.0"),
+      { app_version: "v1.0.0-alpha" },
+      true,
+    ],
+    [
+      "v-prefix, not equal",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "v1.2.4" },
+      true,
+    ],
+    [
+      "v-prefix, at or below",
+      semverRule("app_version", "<=", "1.2.3"),
+      { app_version: "v1.2.3" },
+      true,
+    ],
+    [
+      "v-prefix, greater",
+      semverRule("app_version", ">", "1.2.3"),
+      { app_version: "v1.2.4" },
+      true,
+    ],
+    [
+      "v-prefix, at or above",
+      semverRule("app_version", ">=", "1.2.3"),
+      { app_version: "v1.2.3" },
+      true,
+    ],
+    [
+      "lenient minor-only target",
+      semverRule("app_version", "=", "1.2"),
+      { app_version: "1.2.0" },
+      true,
+    ],
     // Every symbol is asserted in both directions.
-    ["is not, equal", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3" }, false],
-    ["less or equal, above", semverRule("app_version", "<=", "1.2.3"), { app_version: "1.2.4" }, false],
-    ["greater than, below", semverRule("app_version", ">", "1.2.3"), { app_version: "1.2.2" }, false],
-    ["greater or equal, below", semverRule("app_version", ">=", "1.2.3"), { app_version: "1.2.2" }, false],
+    [
+      "is not, equal",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3" },
+      false,
+    ],
+    [
+      "less or equal, above",
+      semverRule("app_version", "<=", "1.2.3"),
+      { app_version: "1.2.4" },
+      false,
+    ],
+    [
+      "greater than, below",
+      semverRule("app_version", ">", "1.2.3"),
+      { app_version: "1.2.2" },
+      false,
+    ],
+    [
+      "greater or equal, below",
+      semverRule("app_version", ">=", "1.2.3"),
+      { app_version: "1.2.2" },
+      false,
+    ],
     // Prerelease precedence, SemVer 2.0.0 section 11.
-    ["prerelease alpha before beta", semverRule("app_version", "<", "1.0.0-beta"), { app_version: "1.0.0-alpha" }, true],
-    ["prerelease beta before rc1", semverRule("app_version", "<", "1.0.0-rc1"), { app_version: "1.0.0-beta" }, true],
-    ["prerelease rc1 before rc2", semverRule("app_version", "<", "1.0.0-rc2"), { app_version: "1.0.0-rc1" }, true],
-    ["more prerelease fields wins", semverRule("app_version", "<", "1.0.0-alpha.1"), { app_version: "1.0.0-alpha" }, true],
-    ["numeric identifier below alphanumeric", semverRule("app_version", "<", "1.0.0-alpha.beta"), { app_version: "1.0.0-alpha.1" }, true],
-    ["fewer fields below alphanumeric", semverRule("app_version", "<", "1.0.0-alpha.beta"), { app_version: "1.0.0-alpha" }, true],
-    ["numeric identifiers compare numerically", semverRule("app_version", "<", "1.0.0-beta.11"), { app_version: "1.0.0-beta.2" }, true],
-    ["dotted identifier ordering, letters", semverRule("app_version", "<", "1.0.0-b.1"), { app_version: "1.0.0-a.1" }, true],
-    ["dotted identifier ordering, digits", semverRule("app_version", "<", "1.0.0-a.2"), { app_version: "1.0.0-a.1" }, true],
-    ["identical prereleases are equal", semverRule("app_version", "=", "1.0.0-rc1"), { app_version: "1.0.0-rc1" }, true],
-    ["rc1 outranks dotted rc.1", semverRule("app_version", ">", "1.0.0-rc.1"), { app_version: "1.0.0-rc1" }, true],
-    ["core version dominates prerelease", semverRule("app_version", ">", "1.9.9"), { app_version: "2.0.0-alpha" }, true],
+    [
+      "prerelease alpha before beta",
+      semverRule("app_version", "<", "1.0.0-beta"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "prerelease beta before rc1",
+      semverRule("app_version", "<", "1.0.0-rc1"),
+      { app_version: "1.0.0-beta" },
+      true,
+    ],
+    [
+      "prerelease rc1 before rc2",
+      semverRule("app_version", "<", "1.0.0-rc2"),
+      { app_version: "1.0.0-rc1" },
+      true,
+    ],
+    [
+      "more prerelease fields wins",
+      semverRule("app_version", "<", "1.0.0-alpha.1"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "numeric identifier below alphanumeric",
+      semverRule("app_version", "<", "1.0.0-alpha.beta"),
+      { app_version: "1.0.0-alpha.1" },
+      true,
+    ],
+    [
+      "fewer fields below alphanumeric",
+      semverRule("app_version", "<", "1.0.0-alpha.beta"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "numeric identifiers compare numerically",
+      semverRule("app_version", "<", "1.0.0-beta.11"),
+      { app_version: "1.0.0-beta.2" },
+      true,
+    ],
+    [
+      "dotted identifier ordering, letters",
+      semverRule("app_version", "<", "1.0.0-b.1"),
+      { app_version: "1.0.0-a.1" },
+      true,
+    ],
+    [
+      "dotted identifier ordering, digits",
+      semverRule("app_version", "<", "1.0.0-a.2"),
+      { app_version: "1.0.0-a.1" },
+      true,
+    ],
+    [
+      "identical prereleases are equal",
+      semverRule("app_version", "=", "1.0.0-rc1"),
+      { app_version: "1.0.0-rc1" },
+      true,
+    ],
+    [
+      "rc1 outranks dotted rc.1",
+      semverRule("app_version", ">", "1.0.0-rc.1"),
+      { app_version: "1.0.0-rc1" },
+      true,
+    ],
+    [
+      "core version dominates prerelease",
+      semverRule("app_version", ">", "1.9.9"),
+      { app_version: "2.0.0-alpha" },
+      true,
+    ],
     // A release outranks its own prerelease, asserted from both sides and under every symbol.
-    ["release outranks its prerelease", semverRule("app_version", ">", "1.0.0-alpha"), { app_version: "1.0.0" }, true],
-    ["release at or above its prerelease", semverRule("app_version", ">=", "1.0.0-rc1"), { app_version: "1.0.0" }, true],
-    ["release differs from its prerelease", semverRule("app_version", "!=", "1.0.0-alpha"), { app_version: "1.0.0" }, true],
-    ["prerelease differs from its release", semverRule("app_version", "!=", "1.0.0"), { app_version: "1.0.0-alpha" }, true],
-    ["prerelease at or below its release", semverRule("app_version", "<=", "1.0.0"), { app_version: "1.0.0-alpha" }, true],
-    ["prerelease of a higher core still wins", semverRule("app_version", ">", "0.9.9"), { app_version: "1.0.0-alpha" }, true],
-    ["prerelease below the next patch", semverRule("app_version", "<", "1.0.1"), { app_version: "1.0.0-rc1" }, true],
+    [
+      "release outranks its prerelease",
+      semverRule("app_version", ">", "1.0.0-alpha"),
+      { app_version: "1.0.0" },
+      true,
+    ],
+    [
+      "release at or above its prerelease",
+      semverRule("app_version", ">=", "1.0.0-rc1"),
+      { app_version: "1.0.0" },
+      true,
+    ],
+    [
+      "release differs from its prerelease",
+      semverRule("app_version", "!=", "1.0.0-alpha"),
+      { app_version: "1.0.0" },
+      true,
+    ],
+    [
+      "prerelease differs from its release",
+      semverRule("app_version", "!=", "1.0.0"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "prerelease at or below its release",
+      semverRule("app_version", "<=", "1.0.0"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "prerelease of a higher core still wins",
+      semverRule("app_version", ">", "0.9.9"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "prerelease below the next patch",
+      semverRule("app_version", "<", "1.0.1"),
+      { app_version: "1.0.0-rc1" },
+      true,
+    ],
     // Prerelease identifier comparison, SemVer 2.0.0 section 11.4.
-    ["numeric identifiers are not compared lexically", semverRule("app_version", "<", "1.0.0-10"), { app_version: "1.0.0-2" }, true],
-    ["numeric identifier ranks below alphanumeric", semverRule("app_version", "<", "1.0.0-alpha"), { app_version: "1.0.0-1" }, true],
-    ["hyphen inside an identifier sorts by ascii", semverRule("app_version", "<", "1.0.0-alpha-1"), { app_version: "1.0.0-alpha" }, true],
-    ["beta ranks below rc", semverRule("app_version", "<", "1.0.0-rc.1"), { app_version: "1.0.0-beta.11" }, true],
-    ["last prerelease ranks below the release", semverRule("app_version", "<", "1.0.0"), { app_version: "1.0.0-rc.1" }, true],
+    [
+      "numeric identifiers are not compared lexically",
+      semverRule("app_version", "<", "1.0.0-10"),
+      { app_version: "1.0.0-2" },
+      true,
+    ],
+    [
+      "numeric identifier ranks below alphanumeric",
+      semverRule("app_version", "<", "1.0.0-alpha"),
+      { app_version: "1.0.0-1" },
+      true,
+    ],
+    [
+      "hyphen inside an identifier sorts by ascii",
+      semverRule("app_version", "<", "1.0.0-alpha-1"),
+      { app_version: "1.0.0-alpha" },
+      true,
+    ],
+    [
+      "beta ranks below rc",
+      semverRule("app_version", "<", "1.0.0-rc.1"),
+      { app_version: "1.0.0-beta.11" },
+      true,
+    ],
+    [
+      "last prerelease ranks below the release",
+      semverRule("app_version", "<", "1.0.0"),
+      { app_version: "1.0.0-rc.1" },
+      true,
+    ],
     // Build metadata carries no precedence.
-    ["build metadata ignored", semverRule("app_version", "=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, true],
-    ["build metadata ignored with prerelease", semverRule("app_version", "=", "1.0.0-alpha"), { app_version: "1.0.0-alpha+build" }, true],
-    ["build metadata with hyphen ignored", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3+build.1-2" }, true],
+    [
+      "build metadata ignored",
+      semverRule("app_version", "=", "1.0.0+build2"),
+      { app_version: "1.0.0+build1" },
+      true,
+    ],
+    [
+      "build metadata ignored with prerelease",
+      semverRule("app_version", "=", "1.0.0-alpha"),
+      { app_version: "1.0.0-alpha+build" },
+      true,
+    ],
+    [
+      "build metadata with hyphen ignored",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3+build.1-2" },
+      true,
+    ],
     // Ignored means equal, so every symbol has to agree with that.
-    ["build metadata leaves versions equal", semverRule("app_version", "!=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, false],
-    ["build metadata is not less", semverRule("app_version", "<", "1.0.0+build2"), { app_version: "1.0.0+build1" }, false],
-    ["build metadata is not greater", semverRule("app_version", ">", "1.0.0+build2"), { app_version: "1.0.0+build1" }, false],
-    ["build metadata at or below", semverRule("app_version", "<=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, true],
-    ["build metadata at or above", semverRule("app_version", ">=", "1.0.0+build2"), { app_version: "1.0.0+build1" }, true],
-    ["build metadata does not block ordering", semverRule("app_version", "<", "1.0.1+build1"), { app_version: "1.0.0+build9" }, true],
-    ["build metadata does not block reverse ordering", semverRule("app_version", ">", "1.0.0+build9"), { app_version: "1.0.1+build1" }, true],
+    [
+      "build metadata leaves versions equal",
+      semverRule("app_version", "!=", "1.0.0+build2"),
+      { app_version: "1.0.0+build1" },
+      false,
+    ],
+    [
+      "build metadata is not less",
+      semverRule("app_version", "<", "1.0.0+build2"),
+      { app_version: "1.0.0+build1" },
+      false,
+    ],
+    [
+      "build metadata is not greater",
+      semverRule("app_version", ">", "1.0.0+build2"),
+      { app_version: "1.0.0+build1" },
+      false,
+    ],
+    [
+      "build metadata at or below",
+      semverRule("app_version", "<=", "1.0.0+build2"),
+      { app_version: "1.0.0+build1" },
+      true,
+    ],
+    [
+      "build metadata at or above",
+      semverRule("app_version", ">=", "1.0.0+build2"),
+      { app_version: "1.0.0+build1" },
+      true,
+    ],
+    [
+      "build metadata does not block ordering",
+      semverRule("app_version", "<", "1.0.1+build1"),
+      { app_version: "1.0.0+build9" },
+      true,
+    ],
+    [
+      "build metadata does not block reverse ordering",
+      semverRule("app_version", ">", "1.0.0+build9"),
+      { app_version: "1.0.1+build1" },
+      true,
+    ],
     // Partial versions keep their prerelease once zero-padded.
-    ["partial version with prerelease", semverRule("app_version", "=", "1.2.0-alpha"), { app_version: "1.2-alpha" }, true],
-    ["partial prerelease below later minor", semverRule("app_version", "<", "1.3.1"), { app_version: "1.2-alpha" }, true],
-    ["partial prerelease below its release", semverRule("app_version", "<", "1.2.0"), { app_version: "1.2-alpha" }, true],
-    ["major-only with prerelease", semverRule("app_version", "<", "1.0.0"), { app_version: "1-rc1" }, true],
+    [
+      "partial version with prerelease",
+      semverRule("app_version", "=", "1.2.0-alpha"),
+      { app_version: "1.2-alpha" },
+      true,
+    ],
+    [
+      "partial prerelease below later minor",
+      semverRule("app_version", "<", "1.3.1"),
+      { app_version: "1.2-alpha" },
+      true,
+    ],
+    [
+      "partial prerelease below its release",
+      semverRule("app_version", "<", "1.2.0"),
+      { app_version: "1.2-alpha" },
+      true,
+    ],
+    [
+      "major-only with prerelease",
+      semverRule("app_version", "<", "1.0.0"),
+      { app_version: "1-rc1" },
+      true,
+    ],
     // An empty prerelease is invalid, so it is rejected rather than treated as the bare release.
-    ["empty prerelease, no match", semverRule("app_version", "=", "1.0.0"), { app_version: "1.0.0-" }, false],
-    ["empty prerelease, not-equal also false", semverRule("app_version", "!=", "1.0.0"), { app_version: "1.0.0-" }, false],
-    ["empty prerelease on partial version, no match", semverRule("app_version", "=", "1.2.0"), { app_version: "1.2-" }, false],
-    ["empty prerelease on partial version, not-equal also false", semverRule("app_version", "!=", "1.2.0"), { app_version: "1.2-" }, false],
+    [
+      "empty prerelease, no match",
+      semverRule("app_version", "=", "1.0.0"),
+      { app_version: "1.0.0-" },
+      false,
+    ],
+    [
+      "empty prerelease, not-equal also false",
+      semverRule("app_version", "!=", "1.0.0"),
+      { app_version: "1.0.0-" },
+      false,
+    ],
+    [
+      "empty prerelease on partial version, no match",
+      semverRule("app_version", "=", "1.2.0"),
+      { app_version: "1.2-" },
+      false,
+    ],
+    [
+      "empty prerelease on partial version, not-equal also false",
+      semverRule("app_version", "!=", "1.2.0"),
+      { app_version: "1.2-" },
+      false,
+    ],
     // Hyphens are legal inside a prerelease identifier, so these are NOT empty prereleases.
-    ["trailing hyphen inside identifier", semverRule("app_version", "<", "1.0.0"), { app_version: "1.0.0-alpha-" }, true],
+    [
+      "trailing hyphen inside identifier",
+      semverRule("app_version", "<", "1.0.0"),
+      { app_version: "1.0.0-alpha-" },
+      true,
+    ],
     // SemVer 2.0.0 forbids leading zeros in the core, so these are rejected rather than normalized.
-    ["leading zero in major, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "01.2.3" }, false],
-    ["leading zero in major, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "01.2.3" }, false],
-    ["leading zero in minor, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.02.3" }, false],
-    ["leading zero in minor, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.02.3" }, false],
-    ["leading zero in patch, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.03" }, false],
-    ["leading zero in patch, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.03" }, false],
-    ["leading zeros throughout, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "01.02.03" }, false],
-    ["leading zeros throughout, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "01.02.03" }, false],
+    [
+      "leading zero in major, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "01.2.3" },
+      false,
+    ],
+    [
+      "leading zero in major, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "01.2.3" },
+      false,
+    ],
+    [
+      "leading zero in minor, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.02.3" },
+      false,
+    ],
+    [
+      "leading zero in minor, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.02.3" },
+      false,
+    ],
+    [
+      "leading zero in patch, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.03" },
+      false,
+    ],
+    [
+      "leading zero in patch, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.03" },
+      false,
+    ],
+    [
+      "leading zeros throughout, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "01.02.03" },
+      false,
+    ],
+    [
+      "leading zeros throughout, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "01.02.03" },
+      false,
+    ],
     // A numeric prerelease identifier may not carry a leading zero either (section 9).
-    ["numeric prerelease with leading zero, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-01" }, false],
-    ["numeric prerelease with leading zero, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-01" }, false],
-    ["dotted numeric prerelease with leading zero, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-rc.01" }, false],
-    ["dotted numeric prerelease with leading zero, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-rc.01" }, false],
+    [
+      "numeric prerelease with leading zero, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3-01" },
+      false,
+    ],
+    [
+      "numeric prerelease with leading zero, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3-01" },
+      false,
+    ],
+    [
+      "dotted numeric prerelease with leading zero, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3-rc.01" },
+      false,
+    ],
+    [
+      "dotted numeric prerelease with leading zero, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3-rc.01" },
+      false,
+    ],
     // An alphanumeric identifier may contain digits, so this one stays valid.
-    ["alphanumeric prerelease with digits", semverRule("app_version", "<", "1.2.3"), { app_version: "1.2.3-rc01" }, true],
-    ["between, inside", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.5.0" }, true],
-    ["between, low boundary inclusive", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.2.3" }, true],
-    ["between, high boundary inclusive", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "2.0.0" }, true],
-    ["between, below", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.0.0" }, false],
-    ["between, above", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "2.0.1" }, false],
+    [
+      "alphanumeric prerelease with digits",
+      semverRule("app_version", "<", "1.2.3"),
+      { app_version: "1.2.3-rc01" },
+      true,
+    ],
+    [
+      "between, inside",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "1.5.0" },
+      true,
+    ],
+    [
+      "between, low boundary inclusive",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "1.2.3" },
+      true,
+    ],
+    [
+      "between, high boundary inclusive",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "2.0.0" },
+      true,
+    ],
+    [
+      "between, below",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "1.0.0" },
+      false,
+    ],
+    [
+      "between, above",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "2.0.1" },
+      false,
+    ],
     // A prerelease sits below its own release, which decides both boundary cases.
-    ["between, prerelease inside", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.5.0-rc1" }, true],
-    ["between, prerelease below the high bound", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "2.0.0-rc1" }, true],
-    ["between, prerelease of the low bound falls out", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "1.2.3-rc1" }, false],
-    ["between, invalid version", customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"), { app_version: "not-a-version" }, false],
-    ["between, single-point range", customBetween("semver_compare", "app_version", "1.2.3", "1.2.3"), { app_version: "1.2.3" }, true],
+    [
+      "between, prerelease inside",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "1.5.0-rc1" },
+      true,
+    ],
+    [
+      "between, prerelease below the high bound",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "2.0.0-rc1" },
+      true,
+    ],
+    [
+      "between, prerelease of the low bound falls out",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "1.2.3-rc1" },
+      false,
+    ],
+    [
+      "between, invalid version",
+      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
+      { app_version: "not-a-version" },
+      false,
+    ],
+    [
+      "between, single-point range",
+      customBetween("semver_compare", "app_version", "1.2.3", "1.2.3"),
+      { app_version: "1.2.3" },
+      true,
+    ],
     // Fail-closed: unparseable or missing values never match.
-    ["invalid actual, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "not-a-version" }, false],
-    ["non-string actual, no match", semverRule("app_version", "=", "1.2.3"), { app_version: 123 }, false],
-    ["missing property, no match", semverRule("app_version", "=", "1.2.3"), {}, false],
+    [
+      "invalid actual, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "not-a-version" },
+      false,
+    ],
+    [
+      "non-string actual, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: 123 },
+      false,
+    ],
+    [
+      "missing property, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      {},
+      false,
+    ],
     // A malformed version must never be padded or coerced into a real one. Both symbols are
     // asserted so that "accepted at all" is observable rather than masked by a single false.
-    ["empty version, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "" }, false],
-    ["empty version, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "" }, false],
-    ["bare v, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "v" }, false],
-    ["bare v, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "v" }, false],
-    ["leading separator, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "-1.2.3" }, false],
-    ["leading separator, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "-1.2.3" }, false],
-    ["trailing dot, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1." }, false],
-    ["trailing dot, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1." }, false],
-    ["trailing dot after patch, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3." }, false],
-    ["trailing dot after patch, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3." }, false],
-    ["empty middle segment, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1..2" }, false],
-    ["empty middle segment, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1..2" }, false],
-    ["four components, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3.4" }, false],
-    ["four components, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3.4" }, false],
-    ["range prefix, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "^1.2.3" }, false],
-    ["range prefix, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "^1.2.3" }, false],
-    ["version inside text, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "abc1.2.3" }, false],
-    ["version inside text, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "abc1.2.3" }, false],
-    ["empty build metadata, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3+" }, false],
-    ["empty build metadata, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3+" }, false],
-    ["empty prerelease identifier, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-alpha..1" }, false],
-    ["empty prerelease identifier, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-alpha..1" }, false],
-    ["lone dot prerelease, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-." }, false],
-    ["lone dot prerelease, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-." }, false],
-    ["underscore in prerelease, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "1.2.3-ALPHA_BETA" }, false],
-    ["underscore in prerelease, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "1.2.3-ALPHA_BETA" }, false],
-    ["doubled v-prefix, no match", semverRule("app_version", "=", "1.2.3"), { app_version: "vv1.2.3" }, false],
-    ["doubled v-prefix, not-equal also false", semverRule("app_version", "!=", "1.2.3"), { app_version: "vv1.2.3" }, false],
-    ["missing operand, no match", { semver_compare: [varNode("app_version"), "="] }, { app_version: "1.2.3" }, false],
+    [
+      "empty version, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "" },
+      false,
+    ],
+    [
+      "empty version, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "" },
+      false,
+    ],
+    [
+      "bare v, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "v" },
+      false,
+    ],
+    [
+      "bare v, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "v" },
+      false,
+    ],
+    [
+      "leading separator, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "-1.2.3" },
+      false,
+    ],
+    [
+      "leading separator, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "-1.2.3" },
+      false,
+    ],
+    [
+      "trailing dot, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1." },
+      false,
+    ],
+    [
+      "trailing dot, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1." },
+      false,
+    ],
+    [
+      "trailing dot after patch, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3." },
+      false,
+    ],
+    [
+      "trailing dot after patch, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3." },
+      false,
+    ],
+    [
+      "empty middle segment, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1..2" },
+      false,
+    ],
+    [
+      "empty middle segment, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1..2" },
+      false,
+    ],
+    [
+      "four components, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3.4" },
+      false,
+    ],
+    [
+      "four components, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3.4" },
+      false,
+    ],
+    [
+      "range prefix, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "^1.2.3" },
+      false,
+    ],
+    [
+      "range prefix, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "^1.2.3" },
+      false,
+    ],
+    [
+      "version inside text, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "abc1.2.3" },
+      false,
+    ],
+    [
+      "version inside text, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "abc1.2.3" },
+      false,
+    ],
+    [
+      "empty build metadata, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3+" },
+      false,
+    ],
+    [
+      "empty build metadata, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3+" },
+      false,
+    ],
+    [
+      "empty prerelease identifier, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3-alpha..1" },
+      false,
+    ],
+    [
+      "empty prerelease identifier, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3-alpha..1" },
+      false,
+    ],
+    [
+      "lone dot prerelease, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3-." },
+      false,
+    ],
+    [
+      "lone dot prerelease, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3-." },
+      false,
+    ],
+    [
+      "underscore in prerelease, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "1.2.3-ALPHA_BETA" },
+      false,
+    ],
+    [
+      "underscore in prerelease, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "1.2.3-ALPHA_BETA" },
+      false,
+    ],
+    [
+      "doubled v-prefix, no match",
+      semverRule("app_version", "=", "1.2.3"),
+      { app_version: "vv1.2.3" },
+      false,
+    ],
+    [
+      "doubled v-prefix, not-equal also false",
+      semverRule("app_version", "!=", "1.2.3"),
+      { app_version: "vv1.2.3" },
+      false,
+    ],
+    [
+      "missing operand, no match",
+      { semver_compare: [varNode("app_version"), "="] },
+      { app_version: "1.2.3" },
+      false,
+    ],
   ])("%s", (_name, rule, data, want) => {
     expect(apply(rule, data)).toBe(want);
   });
@@ -182,92 +779,467 @@ describe("semver_compare operator", () => {
 describe("datetime_compare operator", () => {
   it.each([
     // Asymmetric contract: subject (runtime var) is a strict RFC3339 string, target is epoch ms.
-    ["before, true", datetimeRule("signup", "<", JUL16_MS), { signup: "2026-07-15T00:00:00Z" }, true],
-    ["before, false", datetimeRule("signup", "<", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, false],
-    ["on (equal), true", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, true],
-    ["not on, true", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, true],
-    ["since (>=), boundary", datetimeRule("signup", ">=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, true],
-    ["after (>), true", datetimeRule("signup", ">", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, true],
-    ["after (>), false", datetimeRule("signup", ">", JUL16_MS), { signup: "2026-07-15T00:00:00Z" }, false],
+    [
+      "before, true",
+      datetimeRule("signup", "<", JUL16_MS),
+      { signup: "2026-07-15T00:00:00Z" },
+      true,
+    ],
+    [
+      "before, false",
+      datetimeRule("signup", "<", JUL16_MS),
+      { signup: "2026-07-16T00:00:00Z" },
+      false,
+    ],
+    [
+      "on (equal), true",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00Z" },
+      true,
+    ],
+    [
+      "not on, true",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-17T00:00:00Z" },
+      true,
+    ],
+    [
+      "since (>=), boundary",
+      datetimeRule("signup", ">=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00Z" },
+      true,
+    ],
+    [
+      "after (>), true",
+      datetimeRule("signup", ">", JUL16_MS),
+      { signup: "2026-07-17T00:00:00Z" },
+      true,
+    ],
+    [
+      "after (>), false",
+      datetimeRule("signup", ">", JUL16_MS),
+      { signup: "2026-07-15T00:00:00Z" },
+      false,
+    ],
     // Every symbol is asserted in both directions.
-    ["at or before, boundary", datetimeRule("signup", "<=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, true],
-    ["at or before, after", datetimeRule("signup", "<=", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, false],
-    ["on (equal), false", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-17T00:00:00Z" }, false],
-    ["not on, equal", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00Z" }, false],
-    ["since (>=), before", datetimeRule("signup", ">=", JUL16_MS), { signup: "2026-07-15T00:00:00Z" }, false],
-    ["between, inside", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2026-06-15T00:00:00Z" }, true],
-    ["between, low boundary inclusive", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2026-01-01T00:00:00Z" }, true],
-    ["between, high boundary inclusive", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2026-12-31T00:00:00Z" }, true],
-    ["between, before range", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2025-12-31T00:00:00Z" }, false],
-    ["between, after range", datetimeBetween("signup", JAN1_MS, DEC31_MS), { signup: "2027-01-01T00:00:00Z" }, false],
+    [
+      "at or before, boundary",
+      datetimeRule("signup", "<=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00Z" },
+      true,
+    ],
+    [
+      "at or before, after",
+      datetimeRule("signup", "<=", JUL16_MS),
+      { signup: "2026-07-17T00:00:00Z" },
+      false,
+    ],
+    [
+      "on (equal), false",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-17T00:00:00Z" },
+      false,
+    ],
+    [
+      "not on, equal",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00Z" },
+      false,
+    ],
+    [
+      "since (>=), before",
+      datetimeRule("signup", ">=", JUL16_MS),
+      { signup: "2026-07-15T00:00:00Z" },
+      false,
+    ],
+    [
+      "between, inside",
+      datetimeBetween("signup", JAN1_MS, DEC31_MS),
+      { signup: "2026-06-15T00:00:00Z" },
+      true,
+    ],
+    [
+      "between, low boundary inclusive",
+      datetimeBetween("signup", JAN1_MS, DEC31_MS),
+      { signup: "2026-01-01T00:00:00Z" },
+      true,
+    ],
+    [
+      "between, high boundary inclusive",
+      datetimeBetween("signup", JAN1_MS, DEC31_MS),
+      { signup: "2026-12-31T00:00:00Z" },
+      true,
+    ],
+    [
+      "between, before range",
+      datetimeBetween("signup", JAN1_MS, DEC31_MS),
+      { signup: "2025-12-31T00:00:00Z" },
+      false,
+    ],
+    [
+      "between, after range",
+      datetimeBetween("signup", JAN1_MS, DEC31_MS),
+      { signup: "2027-01-01T00:00:00Z" },
+      false,
+    ],
     // A leap day is a real date.
-    ["leap day", datetimeRule("signup", "=", LEAP_DAY_MS), { signup: "2024-02-29T00:00:00Z" }, true],
+    [
+      "leap day",
+      datetimeRule("signup", "=", LEAP_DAY_MS),
+      { signup: "2024-02-29T00:00:00Z" },
+      true,
+    ],
     // Time-zone offsets change the instant.
-    ["offset with half-hour minutes", datetimeRule("signup", "=", JUL16_INDIA_MS), { signup: "2026-07-16T00:00:00+05:30" }, true],
-    ["rfc3339 subject with offset", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T02:00:00+02:00" }, true],
-    ["positive offset precedes utc midnight", datetimeRule("signup", "<", JUL16_MS), { signup: "2026-07-16T00:00:00+05:30" }, true],
-    ["negative offset", datetimeRule("signup", "=", JUL16_PACIFIC_MS), { signup: "2026-07-16T00:00:00-08:00" }, true],
-    ["negative offset follows utc midnight", datetimeRule("signup", ">", JUL16_MS), { signup: "2026-07-16T00:00:00-08:00" }, true],
-    ["zero offset equals Z", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00+00:00" }, true],
+    [
+      "offset with half-hour minutes",
+      datetimeRule("signup", "=", JUL16_INDIA_MS),
+      { signup: "2026-07-16T00:00:00+05:30" },
+      true,
+    ],
+    [
+      "rfc3339 subject with offset",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T02:00:00+02:00" },
+      true,
+    ],
+    [
+      "positive offset precedes utc midnight",
+      datetimeRule("signup", "<", JUL16_MS),
+      { signup: "2026-07-16T00:00:00+05:30" },
+      true,
+    ],
+    [
+      "negative offset",
+      datetimeRule("signup", "=", JUL16_PACIFIC_MS),
+      { signup: "2026-07-16T00:00:00-08:00" },
+      true,
+    ],
+    [
+      "negative offset follows utc midnight",
+      datetimeRule("signup", ">", JUL16_MS),
+      { signup: "2026-07-16T00:00:00-08:00" },
+      true,
+    ],
+    [
+      "zero offset equals Z",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00+00:00" },
+      true,
+    ],
     // Sub-second precision is dropped, on both sides. The end-of-day rows are the window the UI
     // emits for a single date, whose upper bound carries .999.
-    ["one-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.5Z" }, true],
-    ["three-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.500Z" }, true],
-    ["six-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.123456Z" }, true],
-    ["nine-digit fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.999999999Z" }, true],
-    ["zero fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.0Z" }, true],
-    ["fractional seconds truncated", datetimeRule("signup", ">=", JUL16_MS), { signup: "2026-07-16T00:00:00.500Z" }, true],
-    ["end-of-day target drops its .999", datetimeRule("signup", "=", JUL16_END_MS), { signup: "2026-07-16T23:59:59Z" }, true],
-    ["end-of-day target is an inclusive bound", datetimeRule("signup", "<=", JUL16_END_MS), { signup: "2026-07-16T23:59:59Z" }, true],
-    ["end-of-day, fractional subject too", datetimeRule("signup", "=", JUL16_END_MS), { signup: "2026-07-16T23:59:59.999Z" }, true],
-    ["end-of-day inclusive, fractional subject", datetimeRule("signup", "<=", JUL16_END_MS), { signup: "2026-07-16T23:59:59.999Z" }, true],
+    [
+      "one-digit fraction",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.5Z" },
+      true,
+    ],
+    [
+      "three-digit fraction",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.500Z" },
+      true,
+    ],
+    [
+      "six-digit fraction",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.123456Z" },
+      true,
+    ],
+    [
+      "nine-digit fraction",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.999999999Z" },
+      true,
+    ],
+    [
+      "zero fraction",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.0Z" },
+      true,
+    ],
+    [
+      "fractional seconds truncated",
+      datetimeRule("signup", ">=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.500Z" },
+      true,
+    ],
+    [
+      "end-of-day target drops its .999",
+      datetimeRule("signup", "=", JUL16_END_MS),
+      { signup: "2026-07-16T23:59:59Z" },
+      true,
+    ],
+    [
+      "end-of-day target is an inclusive bound",
+      datetimeRule("signup", "<=", JUL16_END_MS),
+      { signup: "2026-07-16T23:59:59Z" },
+      true,
+    ],
+    [
+      "end-of-day, fractional subject too",
+      datetimeRule("signup", "=", JUL16_END_MS),
+      { signup: "2026-07-16T23:59:59.999Z" },
+      true,
+    ],
+    [
+      "end-of-day inclusive, fractional subject",
+      datetimeRule("signup", "<=", JUL16_END_MS),
+      { signup: "2026-07-16T23:59:59.999Z" },
+      true,
+    ],
     // Fractional on both sides: the shape the UI actually round-trips.
     // Trimming and lowercasing.
-    ["lowercased subject with fraction", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16t00:00:00.500z" }, true],
-    ["lowercased subject with offset", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16t02:00:00+02:00" }, true],
-    ["whitespace-padded subject", datetimeRule("signup", "=", JUL16_MS), { signup: " 2026-07-16T00:00:00Z " }, true],
-    ["lowercased rfc3339 subject", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16t00:00:00z" }, true],
+    [
+      "lowercased subject with fraction",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16t00:00:00.500z" },
+      true,
+    ],
+    [
+      "lowercased subject with offset",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16t02:00:00+02:00" },
+      true,
+    ],
+    [
+      "whitespace-padded subject",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: " 2026-07-16T00:00:00Z " },
+      true,
+    ],
+    [
+      "lowercased rfc3339 subject",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16t00:00:00z" },
+      true,
+    ],
     // Shape violations, asserted under both = and != so that "accepted at all" is observable.
     // RFC 3339 also permits 24:00:00 as end-of-day. Platforms disagree on it, so no vector
     // asserts it either way.
-    ["one-digit month, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-7-16T00:00:00Z" }, false],
-    ["one-digit month, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-7-16T00:00:00Z" }, false],
-    ["space separator, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16 00:00:00Z" }, false],
-    ["space separator, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16 00:00:00Z" }, false],
-    ["missing zone, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00" }, false],
-    ["missing zone, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00" }, false],
-    ["empty fraction, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00.Z" }, false],
-    ["empty fraction, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00.Z" }, false],
-    ["offset without colon, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00+0200" }, false],
-    ["offset without colon, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00+0200" }, false],
-    ["short offset, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00+02" }, false],
-    ["short offset, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00+02" }, false],
-    ["trailing junk, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00Zextra" }, false],
-    ["trailing junk, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00Zextra" }, false],
-    ["basic format, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "20260716T000000Z" }, false],
-    ["basic format, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "20260716T000000Z" }, false],
-    ["zone after lowercase z, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00z00:00" }, false],
-    ["zone after lowercase z, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00z00:00" }, false],
-    ["comma fractional separator, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00,5Z" }, false],
-    ["comma fractional separator, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16T00:00:00,5Z" }, false],
+    [
+      "one-digit month, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-7-16T00:00:00Z" },
+      false,
+    ],
+    [
+      "one-digit month, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-7-16T00:00:00Z" },
+      false,
+    ],
+    [
+      "space separator, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16 00:00:00Z" },
+      false,
+    ],
+    [
+      "space separator, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16 00:00:00Z" },
+      false,
+    ],
+    [
+      "missing zone, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00" },
+      false,
+    ],
+    [
+      "missing zone, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00" },
+      false,
+    ],
+    [
+      "empty fraction, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.Z" },
+      false,
+    ],
+    [
+      "empty fraction, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00.Z" },
+      false,
+    ],
+    [
+      "offset without colon, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00+0200" },
+      false,
+    ],
+    [
+      "offset without colon, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00+0200" },
+      false,
+    ],
+    [
+      "short offset, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00+02" },
+      false,
+    ],
+    [
+      "short offset, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00+02" },
+      false,
+    ],
+    [
+      "trailing junk, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00Zextra" },
+      false,
+    ],
+    [
+      "trailing junk, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00Zextra" },
+      false,
+    ],
+    [
+      "basic format, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "20260716T000000Z" },
+      false,
+    ],
+    [
+      "basic format, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "20260716T000000Z" },
+      false,
+    ],
+    [
+      "zone after lowercase z, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00z00:00" },
+      false,
+    ],
+    [
+      "zone after lowercase z, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00z00:00" },
+      false,
+    ],
+    [
+      "comma fractional separator, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00,5Z" },
+      false,
+    ],
+    [
+      "comma fractional separator, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00,5Z" },
+      false,
+    ],
     // Fail-closed: subject must be an RFC3339 string, target must be an epoch-ms number.
-    ["numeric subject, no match", datetimeRule("signup", "=", JUL16_MS), { signup: JUL16_MS }, false],
-    ["negative epoch-ms target resolves to -1s", datetimeRule("signup", "=", -1500), { signup: "1969-12-31T23:59:59Z" }, true],
-    ["negative epoch-ms target, not equal", datetimeRule("signup", "!=", -1500), { signup: "1969-12-31T23:59:59Z" }, false],
-    ["negative epoch-ms target, at or after", datetimeRule("signup", ">=", -1500), { signup: "1969-12-31T23:59:59Z" }, true],
-    ["negative epoch-ms target, before", datetimeRule("signup", "<", -1500), { signup: "1969-12-31T23:59:58Z" }, true],
-    ["negative epoch-ms target, after", datetimeRule("signup", ">", -2500), { signup: "1969-12-31T23:59:59Z" }, true],
-    ["subject floors, it does not truncate", datetimeRule("signup", "=", -2000), { signup: "1969-12-31T23:59:58.500Z" }, true],
-    ["subject floors, not to -1s", datetimeRule("signup", "!=", -1000), { signup: "1969-12-31T23:59:58.500Z" }, true],
-    ["target beyond representable range, no match", { datetime_compare: [varNode("signup"), "=", 1e308] }, { signup: "2026-07-16T00:00:00Z" }, false],
-    ["target beyond representable range, greater-than also false", { datetime_compare: [varNode("signup"), ">", 1e308] }, { signup: "2026-07-16T00:00:00Z" }, false],
-    ["target beyond representable range, less-than also false", { datetime_compare: [varNode("signup"), "<", 1e308] }, { signup: "2026-07-16T00:00:00Z" }, false],
-    ["bare date subject, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16" }, false],
-    ["bare date subject, not-equal also false", datetimeRule("signup", "!=", JUL16_MS), { signup: "2026-07-16" }, false],
-    ["zoneless datetime subject, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "2026-07-16T00:00:00" }, false],
-    ["non-datetime string, no match", datetimeRule("signup", "=", JUL16_MS), { signup: "yesterday" }, false],
-    ["missing property, no match", datetimeRule("signup", "=", JUL16_MS), {}, false],
-    ["missing operand, no match", { datetime_compare: [varNode("signup"), "="] }, { signup: "2026-07-16T00:00:00Z" }, false],
+    [
+      "numeric subject, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: JUL16_MS },
+      false,
+    ],
+    [
+      "negative epoch-ms target resolves to -1s",
+      datetimeRule("signup", "=", -1500),
+      { signup: "1969-12-31T23:59:59Z" },
+      true,
+    ],
+    [
+      "negative epoch-ms target, not equal",
+      datetimeRule("signup", "!=", -1500),
+      { signup: "1969-12-31T23:59:59Z" },
+      false,
+    ],
+    [
+      "negative epoch-ms target, at or after",
+      datetimeRule("signup", ">=", -1500),
+      { signup: "1969-12-31T23:59:59Z" },
+      true,
+    ],
+    [
+      "negative epoch-ms target, before",
+      datetimeRule("signup", "<", -1500),
+      { signup: "1969-12-31T23:59:58Z" },
+      true,
+    ],
+    [
+      "negative epoch-ms target, after",
+      datetimeRule("signup", ">", -2500),
+      { signup: "1969-12-31T23:59:59Z" },
+      true,
+    ],
+    [
+      "subject floors, it does not truncate",
+      datetimeRule("signup", "=", -2000),
+      { signup: "1969-12-31T23:59:58.500Z" },
+      true,
+    ],
+    [
+      "subject floors, not to -1s",
+      datetimeRule("signup", "!=", -1000),
+      { signup: "1969-12-31T23:59:58.500Z" },
+      true,
+    ],
+    [
+      "target beyond representable range, no match",
+      { datetime_compare: [varNode("signup"), "=", 1e308] },
+      { signup: "2026-07-16T00:00:00Z" },
+      false,
+    ],
+    [
+      "target beyond representable range, greater-than also false",
+      { datetime_compare: [varNode("signup"), ">", 1e308] },
+      { signup: "2026-07-16T00:00:00Z" },
+      false,
+    ],
+    [
+      "target beyond representable range, less-than also false",
+      { datetime_compare: [varNode("signup"), "<", 1e308] },
+      { signup: "2026-07-16T00:00:00Z" },
+      false,
+    ],
+    [
+      "bare date subject, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16" },
+      false,
+    ],
+    [
+      "bare date subject, not-equal also false",
+      datetimeRule("signup", "!=", JUL16_MS),
+      { signup: "2026-07-16" },
+      false,
+    ],
+    [
+      "zoneless datetime subject, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "2026-07-16T00:00:00" },
+      false,
+    ],
+    [
+      "non-datetime string, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      { signup: "yesterday" },
+      false,
+    ],
+    [
+      "missing property, no match",
+      datetimeRule("signup", "=", JUL16_MS),
+      {},
+      false,
+    ],
+    [
+      "missing operand, no match",
+      { datetime_compare: [varNode("signup"), "="] },
+      { signup: "2026-07-16T00:00:00Z" },
+      false,
+    ],
   ])("%s", (_name, rule, data, want) => {
     expect(apply(rule, data)).toBe(want);
   });

From 9acef3887a0162686b78702747bf7c0bc5b62b91 Mon Sep 17 00:00:00 2001
From: Kwame Efah <37164746+efahk@users.noreply.github.com>
Date: Tue, 25 Aug 2026 00:04:21 +0000
Subject: [PATCH 3/7] hand roll semver and update tests

---
 .../mixpanel/lib/flags/custom_operators.js    |   96 +-
 packages/mixpanel/package.json                |    1 -
 .../mixpanel/test/flags/custom_operators.js   | 1282 +----------------
 .../test-data/datetime_compare_tests.json     |   89 ++
 .../flags/test-data/semver_compare_tests.json |  155 ++
 5 files changed, 391 insertions(+), 1232 deletions(-)
 create mode 100644 packages/mixpanel/test/flags/test-data/datetime_compare_tests.json
 create mode 100644 packages/mixpanel/test/flags/test-data/semver_compare_tests.json

diff --git a/packages/mixpanel/lib/flags/custom_operators.js b/packages/mixpanel/lib/flags/custom_operators.js
index ee79042..7089b8d 100644
--- a/packages/mixpanel/lib/flags/custom_operators.js
+++ b/packages/mixpanel/lib/flags/custom_operators.js
@@ -1,5 +1,4 @@
 const jsonLogic = require("json-logic-js");
-const { compareVersions } = require("compare-versions");
 
 // Strict RFC3339 guard for datetime strings.
 const RFC3339_PATTERN =
@@ -37,10 +36,99 @@ function semverCompare(actual, symbol, target) {
   ) {
     return false;
   }
-  const cmp = compareVersions(actualVersion, targetVersion);
+  const cmp = compareSemver(actualVersion, targetVersion);
   return comparatorMatches(cmp, symbol);
 }
 
+// Strip optional build metadata and separate the core version from pre-release identifiers
+function splitSemver(version) {
+  const plus = version.indexOf("+");
+  if (plus !== -1) {
+    version = version.slice(0, plus);
+  }
+  const dash = version.indexOf("-");
+  if (dash === -1) {
+    return { core: version.split("."), prerelease: [] };
+  }
+  return {
+    core: version.slice(0, dash).split("."),
+    prerelease: version.slice(dash + 1).split("."),
+  };
+}
+
+function isNumericIdentifier(identifier) {
+  return /^[0-9]+$/.test(identifier);
+}
+
+// Numeric identifiers carry no leading zeros, so the longer run of digits is the larger number.
+// Comparing them as digits rather than as numbers keeps versions past Number.MAX_SAFE_INTEGER
+// ordered correctly.
+function compareNumeric(a, b) {
+  if (a.length !== b.length) {
+    return a.length < b.length ? -1 : 1;
+  }
+  return a < b ? -1 : a > b ? 1 : 0;
+}
+
+// SemVer 2.0.0 section 11.4: digits compare numerically, a numeric identifier ranks below an
+// alphanumeric one, and anything else compares by ASCII order.
+function comparePrereleaseIdentifier(a, b) {
+  const aNumeric = isNumericIdentifier(a);
+  const bNumeric = isNumericIdentifier(b);
+  if (aNumeric && bNumeric) {
+    return compareNumeric(a, b);
+  }
+  if (aNumeric) {
+    return -1;
+  }
+  if (bNumeric) {
+    return 1;
+  }
+  return a < b ? -1 : a > b ? 1 : 0;
+}
+
+// Ordering per SemVer 2.0.0 section 11. Both operands have already been normalized and matched
+// against the official regex, so the core holds exactly three numeric identifiers and every
+// prerelease field is well-formed; the split needs no error path.
+function compareSemver(actualVersion, targetVersion) {
+  const actual = splitSemver(actualVersion);
+  const target = splitSemver(targetVersion);
+
+  for (let i = 0; i < actual.core.length; i++) {
+    const result = compareNumeric(actual.core[i], target.core[i]);
+    if (result !== 0) {
+      return result;
+    }
+  }
+
+  // A prerelease ranks below the release it belongs to (section 11.3).
+  if (!actual.prerelease.length && !target.prerelease.length) {
+    return 0;
+  }
+  if (!actual.prerelease.length) {
+    return 1;
+  }
+  if (!target.prerelease.length) {
+    return -1;
+  }
+
+  const shared = Math.min(actual.prerelease.length, target.prerelease.length);
+  for (let i = 0; i < shared; i++) {
+    const result = comparePrereleaseIdentifier(
+      actual.prerelease[i],
+      target.prerelease[i],
+    );
+    if (result !== 0) {
+      return result;
+    }
+  }
+  // Every field so far is equal, so the longer list wins (section 11.4.4).
+  if (actual.prerelease.length !== target.prerelease.length) {
+    return actual.prerelease.length < target.prerelease.length ? -1 : 1;
+  }
+  return 0;
+}
+
 // Implements a custom operation for datetime comparison.
 // The target value stored on the feature flag is the millisecond epoch, whereas the actual value provided at evaluation time must be RFC-3339 formatted.
 function datetimeCompare(actual, symbol, target) {
@@ -58,9 +146,9 @@ function datetimeCompare(actual, symbol, target) {
 
 function comparatorMatches(cmp, symbol) {
   switch (symbol) {
-    case "=":
+    case "===":
       return cmp === 0;
-    case "!=":
+    case "!==":
       return cmp !== 0;
     case "<":
       return cmp < 0;
diff --git a/packages/mixpanel/package.json b/packages/mixpanel/package.json
index 46057c4..39b7d60 100644
--- a/packages/mixpanel/package.json
+++ b/packages/mixpanel/package.json
@@ -35,7 +35,6 @@
     "build": "tsc --build"
   },
   "dependencies": {
-    "compare-versions": "6.1.1",
     "https-proxy-agent": "7.0.6",
     "json-logic-js": "2.0.5"
   },
diff --git a/packages/mixpanel/test/flags/custom_operators.js b/packages/mixpanel/test/flags/custom_operators.js
index c0ebbff..bdff362 100644
--- a/packages/mixpanel/test/flags/custom_operators.js
+++ b/packages/mixpanel/test/flags/custom_operators.js
@@ -1,1246 +1,74 @@
+const fs = require("fs");
+const path = require("path");
+
 const { apply } = require("json-logic-js");
 // Requiring the module registers semver_compare and datetime_compare on the shared
 // json-logic-js instance used by apply().
 require("../../lib/flags/custom_operators");
 
-const varNode = (key) => ({ var: key });
-
-const semverRule = (key, sym, target) => ({
-  semver_compare: [varNode(key), sym, target],
-});
+// The golden vectors are the cross-SDK contract for the custom operators; the canonical copy and
+// its README live in the analytics monorepo. Cases run through apply() so that operator
+// registration is covered alongside the comparison itself.
+const TEST_DATA = path.join(__dirname, "test-data");
 
-const datetimeRule = (key, sym, target) => ({
-  datetime_compare: [varNode(key), sym, target],
-});
+// The property key the vectors are evaluated against. It is plumbing the test supplies, so any name
+// works as long as the rule and the data agree on it.
+const VECTOR_KEY = "value";
 
-const customBetween = (op, key, lo, hi) => ({
-  and: [{ [op]: [varNode(key), ">=", lo] }, { [op]: [varNode(key), "<=", hi] }],
-});
+// Build the event the rule reads from, omitting the key entirely for an unset property.
+function dataFor(subject) {
+  return subject === null ? {} : { [VECTOR_KEY]: subject };
+}
 
-const datetimeBetween = (key, lo, hi) => ({
-  and: [
-    { datetime_compare: [varNode(key), ">=", lo] },
-    { datetime_compare: [varNode(key), "<=", hi] },
-  ],
-});
+// Read a golden-vector file. String entries are headings, array entries are cases.
+function loadVectors(operator) {
+  const entries = JSON.parse(
+    fs.readFileSync(
+      path.join(TEST_DATA, `${operator}_compare_tests.json`),
+      "utf8",
+    ),
+  );
 
-// Epoch-millisecond constants (UTC instants) used as datetime targets, matching the UI format.
-const JUL16_MS = 1_784_160_000_000; // 2026-07-16T00:00:00Z
-const JAN1_MS = 1_767_225_600_000; // 2026-01-01T00:00:00Z
-const DEC31_MS = 1_798_675_200_000; // 2026-12-31T00:00:00Z
-const JUL16_END_MS = 1_784_246_399_999; // 2026-07-16T23:59:59.999Z
-const LEAP_DAY_MS = 1_709_164_800_000; // 2024-02-29T00:00:00Z
-const JUL16_INDIA_MS = 1_784_140_200_000; // 2026-07-16T00:00:00+05:30
-const JUL16_PACIFIC_MS = 1_784_188_800_000; // 2026-07-16T00:00:00-08:00
+  let section = "";
+  const cases = [];
+  entries.forEach((entry, index) => {
+    if (typeof entry === "string") {
+      section = entry;
+      return;
+    }
+    const [subject, symbol, target, want] = entry;
+    const rule = {
+      [`${operator}_compare`]: [{ var: VECTOR_KEY }, symbol, target],
+    };
+    const name = `${index} ${section}: ${JSON.stringify(subject)} ${symbol} ${JSON.stringify(target)}`;
+    cases.push([name, rule, dataFor(subject), want]);
+  });
+  return cases;
+}
 
 describe("semver_compare operator", () => {
-  it.each([
-    [
-      "is, equal",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3" },
-      true,
-    ],
-    [
-      "is, not equal",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.4" },
-      false,
-    ],
-    [
-      "is not",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.4" },
-      true,
-    ],
-    [
-      "less than, patch",
-      semverRule("app_version", "<", "1.2.3"),
-      { app_version: "1.2.2" },
-      true,
-    ],
-    [
-      "less than, false",
-      semverRule("app_version", "<", "1.2.3"),
-      { app_version: "1.2.3" },
-      false,
-    ],
-    [
-      "less or equal, boundary",
-      semverRule("app_version", "<=", "1.2.3"),
-      { app_version: "1.2.3" },
-      true,
-    ],
-    [
-      "greater than, minor",
-      semverRule("app_version", ">", "1.2.3"),
-      { app_version: "1.3.0" },
-      true,
-    ],
-    [
-      "greater or equal, boundary",
-      semverRule("app_version", ">=", "1.2.3"),
-      { app_version: "1.2.3" },
-      true,
-    ],
-    [
-      "double-digit ordering (not lexical)",
-      semverRule("app_version", ">", "1.9.0"),
-      { app_version: "1.10.0" },
-      true,
-    ],
-    [
-      "prerelease precedes release",
-      semverRule("app_version", "<", "1.0.0"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "lenient v-prefix",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "v1.2.3" },
-      true,
-    ],
-    [
-      "lenient uppercase V-prefix",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "V1.2.3" },
-      true,
-    ],
-    [
-      "v-prefix keeps prerelease",
-      semverRule("app_version", "<", "1.0.0"),
-      { app_version: "v1.0.0-alpha" },
-      true,
-    ],
-    [
-      "v-prefix, not equal",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "v1.2.4" },
-      true,
-    ],
-    [
-      "v-prefix, at or below",
-      semverRule("app_version", "<=", "1.2.3"),
-      { app_version: "v1.2.3" },
-      true,
-    ],
-    [
-      "v-prefix, greater",
-      semverRule("app_version", ">", "1.2.3"),
-      { app_version: "v1.2.4" },
-      true,
-    ],
-    [
-      "v-prefix, at or above",
-      semverRule("app_version", ">=", "1.2.3"),
-      { app_version: "v1.2.3" },
-      true,
-    ],
-    [
-      "lenient minor-only target",
-      semverRule("app_version", "=", "1.2"),
-      { app_version: "1.2.0" },
-      true,
-    ],
-    // Every symbol is asserted in both directions.
-    [
-      "is not, equal",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3" },
-      false,
-    ],
-    [
-      "less or equal, above",
-      semverRule("app_version", "<=", "1.2.3"),
-      { app_version: "1.2.4" },
-      false,
-    ],
-    [
-      "greater than, below",
-      semverRule("app_version", ">", "1.2.3"),
-      { app_version: "1.2.2" },
-      false,
-    ],
-    [
-      "greater or equal, below",
-      semverRule("app_version", ">=", "1.2.3"),
-      { app_version: "1.2.2" },
-      false,
-    ],
-    // Prerelease precedence, SemVer 2.0.0 section 11.
-    [
-      "prerelease alpha before beta",
-      semverRule("app_version", "<", "1.0.0-beta"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "prerelease beta before rc1",
-      semverRule("app_version", "<", "1.0.0-rc1"),
-      { app_version: "1.0.0-beta" },
-      true,
-    ],
-    [
-      "prerelease rc1 before rc2",
-      semverRule("app_version", "<", "1.0.0-rc2"),
-      { app_version: "1.0.0-rc1" },
-      true,
-    ],
-    [
-      "more prerelease fields wins",
-      semverRule("app_version", "<", "1.0.0-alpha.1"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "numeric identifier below alphanumeric",
-      semverRule("app_version", "<", "1.0.0-alpha.beta"),
-      { app_version: "1.0.0-alpha.1" },
-      true,
-    ],
-    [
-      "fewer fields below alphanumeric",
-      semverRule("app_version", "<", "1.0.0-alpha.beta"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "numeric identifiers compare numerically",
-      semverRule("app_version", "<", "1.0.0-beta.11"),
-      { app_version: "1.0.0-beta.2" },
-      true,
-    ],
-    [
-      "dotted identifier ordering, letters",
-      semverRule("app_version", "<", "1.0.0-b.1"),
-      { app_version: "1.0.0-a.1" },
-      true,
-    ],
-    [
-      "dotted identifier ordering, digits",
-      semverRule("app_version", "<", "1.0.0-a.2"),
-      { app_version: "1.0.0-a.1" },
-      true,
-    ],
-    [
-      "identical prereleases are equal",
-      semverRule("app_version", "=", "1.0.0-rc1"),
-      { app_version: "1.0.0-rc1" },
-      true,
-    ],
-    [
-      "rc1 outranks dotted rc.1",
-      semverRule("app_version", ">", "1.0.0-rc.1"),
-      { app_version: "1.0.0-rc1" },
-      true,
-    ],
-    [
-      "core version dominates prerelease",
-      semverRule("app_version", ">", "1.9.9"),
-      { app_version: "2.0.0-alpha" },
-      true,
-    ],
-    // A release outranks its own prerelease, asserted from both sides and under every symbol.
-    [
-      "release outranks its prerelease",
-      semverRule("app_version", ">", "1.0.0-alpha"),
-      { app_version: "1.0.0" },
-      true,
-    ],
-    [
-      "release at or above its prerelease",
-      semverRule("app_version", ">=", "1.0.0-rc1"),
-      { app_version: "1.0.0" },
-      true,
-    ],
-    [
-      "release differs from its prerelease",
-      semverRule("app_version", "!=", "1.0.0-alpha"),
-      { app_version: "1.0.0" },
-      true,
-    ],
-    [
-      "prerelease differs from its release",
-      semverRule("app_version", "!=", "1.0.0"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "prerelease at or below its release",
-      semverRule("app_version", "<=", "1.0.0"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "prerelease of a higher core still wins",
-      semverRule("app_version", ">", "0.9.9"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "prerelease below the next patch",
-      semverRule("app_version", "<", "1.0.1"),
-      { app_version: "1.0.0-rc1" },
-      true,
-    ],
-    // Prerelease identifier comparison, SemVer 2.0.0 section 11.4.
-    [
-      "numeric identifiers are not compared lexically",
-      semverRule("app_version", "<", "1.0.0-10"),
-      { app_version: "1.0.0-2" },
-      true,
-    ],
-    [
-      "numeric identifier ranks below alphanumeric",
-      semverRule("app_version", "<", "1.0.0-alpha"),
-      { app_version: "1.0.0-1" },
-      true,
-    ],
-    [
-      "hyphen inside an identifier sorts by ascii",
-      semverRule("app_version", "<", "1.0.0-alpha-1"),
-      { app_version: "1.0.0-alpha" },
-      true,
-    ],
-    [
-      "beta ranks below rc",
-      semverRule("app_version", "<", "1.0.0-rc.1"),
-      { app_version: "1.0.0-beta.11" },
-      true,
-    ],
-    [
-      "last prerelease ranks below the release",
-      semverRule("app_version", "<", "1.0.0"),
-      { app_version: "1.0.0-rc.1" },
-      true,
-    ],
-    // Build metadata carries no precedence.
-    [
-      "build metadata ignored",
-      semverRule("app_version", "=", "1.0.0+build2"),
-      { app_version: "1.0.0+build1" },
-      true,
-    ],
-    [
-      "build metadata ignored with prerelease",
-      semverRule("app_version", "=", "1.0.0-alpha"),
-      { app_version: "1.0.0-alpha+build" },
-      true,
-    ],
-    [
-      "build metadata with hyphen ignored",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3+build.1-2" },
-      true,
-    ],
-    // Ignored means equal, so every symbol has to agree with that.
-    [
-      "build metadata leaves versions equal",
-      semverRule("app_version", "!=", "1.0.0+build2"),
-      { app_version: "1.0.0+build1" },
-      false,
-    ],
-    [
-      "build metadata is not less",
-      semverRule("app_version", "<", "1.0.0+build2"),
-      { app_version: "1.0.0+build1" },
-      false,
-    ],
-    [
-      "build metadata is not greater",
-      semverRule("app_version", ">", "1.0.0+build2"),
-      { app_version: "1.0.0+build1" },
-      false,
-    ],
-    [
-      "build metadata at or below",
-      semverRule("app_version", "<=", "1.0.0+build2"),
-      { app_version: "1.0.0+build1" },
-      true,
-    ],
-    [
-      "build metadata at or above",
-      semverRule("app_version", ">=", "1.0.0+build2"),
-      { app_version: "1.0.0+build1" },
-      true,
-    ],
-    [
-      "build metadata does not block ordering",
-      semverRule("app_version", "<", "1.0.1+build1"),
-      { app_version: "1.0.0+build9" },
-      true,
-    ],
-    [
-      "build metadata does not block reverse ordering",
-      semverRule("app_version", ">", "1.0.0+build9"),
-      { app_version: "1.0.1+build1" },
-      true,
-    ],
-    // Partial versions keep their prerelease once zero-padded.
-    [
-      "partial version with prerelease",
-      semverRule("app_version", "=", "1.2.0-alpha"),
-      { app_version: "1.2-alpha" },
-      true,
-    ],
-    [
-      "partial prerelease below later minor",
-      semverRule("app_version", "<", "1.3.1"),
-      { app_version: "1.2-alpha" },
-      true,
-    ],
-    [
-      "partial prerelease below its release",
-      semverRule("app_version", "<", "1.2.0"),
-      { app_version: "1.2-alpha" },
-      true,
-    ],
-    [
-      "major-only with prerelease",
-      semverRule("app_version", "<", "1.0.0"),
-      { app_version: "1-rc1" },
-      true,
-    ],
-    // An empty prerelease is invalid, so it is rejected rather than treated as the bare release.
-    [
-      "empty prerelease, no match",
-      semverRule("app_version", "=", "1.0.0"),
-      { app_version: "1.0.0-" },
-      false,
-    ],
-    [
-      "empty prerelease, not-equal also false",
-      semverRule("app_version", "!=", "1.0.0"),
-      { app_version: "1.0.0-" },
-      false,
-    ],
-    [
-      "empty prerelease on partial version, no match",
-      semverRule("app_version", "=", "1.2.0"),
-      { app_version: "1.2-" },
-      false,
-    ],
-    [
-      "empty prerelease on partial version, not-equal also false",
-      semverRule("app_version", "!=", "1.2.0"),
-      { app_version: "1.2-" },
-      false,
-    ],
-    // Hyphens are legal inside a prerelease identifier, so these are NOT empty prereleases.
-    [
-      "trailing hyphen inside identifier",
-      semverRule("app_version", "<", "1.0.0"),
-      { app_version: "1.0.0-alpha-" },
-      true,
-    ],
-    // SemVer 2.0.0 forbids leading zeros in the core, so these are rejected rather than normalized.
-    [
-      "leading zero in major, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "01.2.3" },
-      false,
-    ],
-    [
-      "leading zero in major, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "01.2.3" },
-      false,
-    ],
-    [
-      "leading zero in minor, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.02.3" },
-      false,
-    ],
-    [
-      "leading zero in minor, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.02.3" },
-      false,
-    ],
-    [
-      "leading zero in patch, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.03" },
-      false,
-    ],
-    [
-      "leading zero in patch, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.03" },
-      false,
-    ],
-    [
-      "leading zeros throughout, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "01.02.03" },
-      false,
-    ],
-    [
-      "leading zeros throughout, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "01.02.03" },
-      false,
-    ],
-    // A numeric prerelease identifier may not carry a leading zero either (section 9).
-    [
-      "numeric prerelease with leading zero, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3-01" },
-      false,
-    ],
-    [
-      "numeric prerelease with leading zero, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3-01" },
-      false,
-    ],
-    [
-      "dotted numeric prerelease with leading zero, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3-rc.01" },
-      false,
-    ],
-    [
-      "dotted numeric prerelease with leading zero, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3-rc.01" },
-      false,
-    ],
-    // An alphanumeric identifier may contain digits, so this one stays valid.
-    [
-      "alphanumeric prerelease with digits",
-      semverRule("app_version", "<", "1.2.3"),
-      { app_version: "1.2.3-rc01" },
-      true,
-    ],
-    [
-      "between, inside",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "1.5.0" },
-      true,
-    ],
-    [
-      "between, low boundary inclusive",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "1.2.3" },
-      true,
-    ],
-    [
-      "between, high boundary inclusive",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "2.0.0" },
-      true,
-    ],
-    [
-      "between, below",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "1.0.0" },
-      false,
-    ],
-    [
-      "between, above",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "2.0.1" },
-      false,
-    ],
-    // A prerelease sits below its own release, which decides both boundary cases.
-    [
-      "between, prerelease inside",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "1.5.0-rc1" },
-      true,
-    ],
-    [
-      "between, prerelease below the high bound",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "2.0.0-rc1" },
-      true,
-    ],
-    [
-      "between, prerelease of the low bound falls out",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "1.2.3-rc1" },
-      false,
-    ],
-    [
-      "between, invalid version",
-      customBetween("semver_compare", "app_version", "1.2.3", "2.0.0"),
-      { app_version: "not-a-version" },
-      false,
-    ],
-    [
-      "between, single-point range",
-      customBetween("semver_compare", "app_version", "1.2.3", "1.2.3"),
-      { app_version: "1.2.3" },
-      true,
-    ],
-    // Fail-closed: unparseable or missing values never match.
-    [
-      "invalid actual, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "not-a-version" },
-      false,
-    ],
-    [
-      "non-string actual, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: 123 },
-      false,
-    ],
-    [
-      "missing property, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      {},
-      false,
-    ],
-    // A malformed version must never be padded or coerced into a real one. Both symbols are
-    // asserted so that "accepted at all" is observable rather than masked by a single false.
-    [
-      "empty version, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "" },
-      false,
-    ],
-    [
-      "empty version, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "" },
-      false,
-    ],
-    [
-      "bare v, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "v" },
-      false,
-    ],
-    [
-      "bare v, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "v" },
-      false,
-    ],
-    [
-      "leading separator, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "-1.2.3" },
-      false,
-    ],
-    [
-      "leading separator, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "-1.2.3" },
-      false,
-    ],
-    [
-      "trailing dot, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1." },
-      false,
-    ],
-    [
-      "trailing dot, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1." },
-      false,
-    ],
-    [
-      "trailing dot after patch, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3." },
-      false,
-    ],
-    [
-      "trailing dot after patch, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3." },
-      false,
-    ],
-    [
-      "empty middle segment, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1..2" },
-      false,
-    ],
-    [
-      "empty middle segment, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1..2" },
-      false,
-    ],
-    [
-      "four components, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3.4" },
-      false,
-    ],
-    [
-      "four components, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3.4" },
-      false,
-    ],
-    [
-      "range prefix, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "^1.2.3" },
-      false,
-    ],
-    [
-      "range prefix, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "^1.2.3" },
-      false,
-    ],
-    [
-      "version inside text, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "abc1.2.3" },
-      false,
-    ],
-    [
-      "version inside text, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "abc1.2.3" },
-      false,
-    ],
-    [
-      "empty build metadata, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3+" },
-      false,
-    ],
-    [
-      "empty build metadata, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3+" },
-      false,
-    ],
-    [
-      "empty prerelease identifier, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3-alpha..1" },
-      false,
-    ],
-    [
-      "empty prerelease identifier, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3-alpha..1" },
-      false,
-    ],
-    [
-      "lone dot prerelease, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3-." },
-      false,
-    ],
-    [
-      "lone dot prerelease, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3-." },
-      false,
-    ],
-    [
-      "underscore in prerelease, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "1.2.3-ALPHA_BETA" },
-      false,
-    ],
-    [
-      "underscore in prerelease, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "1.2.3-ALPHA_BETA" },
-      false,
-    ],
-    [
-      "doubled v-prefix, no match",
-      semverRule("app_version", "=", "1.2.3"),
-      { app_version: "vv1.2.3" },
-      false,
-    ],
-    [
-      "doubled v-prefix, not-equal also false",
-      semverRule("app_version", "!=", "1.2.3"),
-      { app_version: "vv1.2.3" },
-      false,
-    ],
-    [
-      "missing operand, no match",
-      { semver_compare: [varNode("app_version"), "="] },
-      { app_version: "1.2.3" },
-      false,
-    ],
-  ])("%s", (_name, rule, data, want) => {
+  it.each(loadVectors("semver"))("%s", (_name, rule, data, want) => {
     expect(apply(rule, data)).toBe(want);
   });
 });
 
 describe("datetime_compare operator", () => {
-  it.each([
-    // Asymmetric contract: subject (runtime var) is a strict RFC3339 string, target is epoch ms.
-    [
-      "before, true",
-      datetimeRule("signup", "<", JUL16_MS),
-      { signup: "2026-07-15T00:00:00Z" },
-      true,
-    ],
-    [
-      "before, false",
-      datetimeRule("signup", "<", JUL16_MS),
-      { signup: "2026-07-16T00:00:00Z" },
-      false,
-    ],
-    [
-      "on (equal), true",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00Z" },
-      true,
-    ],
-    [
-      "not on, true",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-17T00:00:00Z" },
-      true,
-    ],
-    [
-      "since (>=), boundary",
-      datetimeRule("signup", ">=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00Z" },
-      true,
-    ],
-    [
-      "after (>), true",
-      datetimeRule("signup", ">", JUL16_MS),
-      { signup: "2026-07-17T00:00:00Z" },
-      true,
-    ],
-    [
-      "after (>), false",
-      datetimeRule("signup", ">", JUL16_MS),
-      { signup: "2026-07-15T00:00:00Z" },
-      false,
-    ],
-    // Every symbol is asserted in both directions.
-    [
-      "at or before, boundary",
-      datetimeRule("signup", "<=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00Z" },
-      true,
-    ],
-    [
-      "at or before, after",
-      datetimeRule("signup", "<=", JUL16_MS),
-      { signup: "2026-07-17T00:00:00Z" },
-      false,
-    ],
-    [
-      "on (equal), false",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-17T00:00:00Z" },
-      false,
-    ],
-    [
-      "not on, equal",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00Z" },
-      false,
-    ],
-    [
-      "since (>=), before",
-      datetimeRule("signup", ">=", JUL16_MS),
-      { signup: "2026-07-15T00:00:00Z" },
-      false,
-    ],
-    [
-      "between, inside",
-      datetimeBetween("signup", JAN1_MS, DEC31_MS),
-      { signup: "2026-06-15T00:00:00Z" },
-      true,
-    ],
-    [
-      "between, low boundary inclusive",
-      datetimeBetween("signup", JAN1_MS, DEC31_MS),
-      { signup: "2026-01-01T00:00:00Z" },
-      true,
-    ],
-    [
-      "between, high boundary inclusive",
-      datetimeBetween("signup", JAN1_MS, DEC31_MS),
-      { signup: "2026-12-31T00:00:00Z" },
-      true,
-    ],
-    [
-      "between, before range",
-      datetimeBetween("signup", JAN1_MS, DEC31_MS),
-      { signup: "2025-12-31T00:00:00Z" },
-      false,
-    ],
-    [
-      "between, after range",
-      datetimeBetween("signup", JAN1_MS, DEC31_MS),
-      { signup: "2027-01-01T00:00:00Z" },
-      false,
-    ],
-    // A leap day is a real date.
-    [
-      "leap day",
-      datetimeRule("signup", "=", LEAP_DAY_MS),
-      { signup: "2024-02-29T00:00:00Z" },
-      true,
-    ],
-    // Time-zone offsets change the instant.
-    [
-      "offset with half-hour minutes",
-      datetimeRule("signup", "=", JUL16_INDIA_MS),
-      { signup: "2026-07-16T00:00:00+05:30" },
-      true,
-    ],
-    [
-      "rfc3339 subject with offset",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T02:00:00+02:00" },
-      true,
-    ],
-    [
-      "positive offset precedes utc midnight",
-      datetimeRule("signup", "<", JUL16_MS),
-      { signup: "2026-07-16T00:00:00+05:30" },
-      true,
-    ],
-    [
-      "negative offset",
-      datetimeRule("signup", "=", JUL16_PACIFIC_MS),
-      { signup: "2026-07-16T00:00:00-08:00" },
-      true,
-    ],
-    [
-      "negative offset follows utc midnight",
-      datetimeRule("signup", ">", JUL16_MS),
-      { signup: "2026-07-16T00:00:00-08:00" },
-      true,
-    ],
-    [
-      "zero offset equals Z",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00+00:00" },
-      true,
-    ],
-    // Sub-second precision is dropped, on both sides. The end-of-day rows are the window the UI
-    // emits for a single date, whose upper bound carries .999.
-    [
-      "one-digit fraction",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.5Z" },
-      true,
-    ],
-    [
-      "three-digit fraction",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.500Z" },
-      true,
-    ],
-    [
-      "six-digit fraction",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.123456Z" },
-      true,
-    ],
-    [
-      "nine-digit fraction",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.999999999Z" },
-      true,
-    ],
-    [
-      "zero fraction",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.0Z" },
-      true,
-    ],
-    [
-      "fractional seconds truncated",
-      datetimeRule("signup", ">=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.500Z" },
-      true,
-    ],
-    [
-      "end-of-day target drops its .999",
-      datetimeRule("signup", "=", JUL16_END_MS),
-      { signup: "2026-07-16T23:59:59Z" },
-      true,
-    ],
-    [
-      "end-of-day target is an inclusive bound",
-      datetimeRule("signup", "<=", JUL16_END_MS),
-      { signup: "2026-07-16T23:59:59Z" },
-      true,
-    ],
-    [
-      "end-of-day, fractional subject too",
-      datetimeRule("signup", "=", JUL16_END_MS),
-      { signup: "2026-07-16T23:59:59.999Z" },
-      true,
-    ],
-    [
-      "end-of-day inclusive, fractional subject",
-      datetimeRule("signup", "<=", JUL16_END_MS),
-      { signup: "2026-07-16T23:59:59.999Z" },
-      true,
-    ],
-    // Fractional on both sides: the shape the UI actually round-trips.
-    // Trimming and lowercasing.
-    [
-      "lowercased subject with fraction",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16t00:00:00.500z" },
-      true,
-    ],
-    [
-      "lowercased subject with offset",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16t02:00:00+02:00" },
-      true,
-    ],
-    [
-      "whitespace-padded subject",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: " 2026-07-16T00:00:00Z " },
-      true,
-    ],
-    [
-      "lowercased rfc3339 subject",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16t00:00:00z" },
-      true,
-    ],
-    // Shape violations, asserted under both = and != so that "accepted at all" is observable.
-    // RFC 3339 also permits 24:00:00 as end-of-day. Platforms disagree on it, so no vector
-    // asserts it either way.
-    [
-      "one-digit month, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-7-16T00:00:00Z" },
-      false,
-    ],
-    [
-      "one-digit month, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-7-16T00:00:00Z" },
-      false,
-    ],
-    [
-      "space separator, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16 00:00:00Z" },
-      false,
-    ],
-    [
-      "space separator, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16 00:00:00Z" },
-      false,
-    ],
-    [
-      "missing zone, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00" },
-      false,
-    ],
-    [
-      "missing zone, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00" },
-      false,
-    ],
-    [
-      "empty fraction, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.Z" },
-      false,
-    ],
-    [
-      "empty fraction, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00.Z" },
-      false,
-    ],
-    [
-      "offset without colon, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00+0200" },
-      false,
-    ],
-    [
-      "offset without colon, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00+0200" },
-      false,
-    ],
-    [
-      "short offset, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00+02" },
-      false,
-    ],
-    [
-      "short offset, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00+02" },
-      false,
-    ],
-    [
-      "trailing junk, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00Zextra" },
-      false,
-    ],
-    [
-      "trailing junk, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00Zextra" },
-      false,
-    ],
-    [
-      "basic format, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "20260716T000000Z" },
-      false,
-    ],
-    [
-      "basic format, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "20260716T000000Z" },
-      false,
-    ],
-    [
-      "zone after lowercase z, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00z00:00" },
-      false,
-    ],
-    [
-      "zone after lowercase z, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00z00:00" },
-      false,
-    ],
-    [
-      "comma fractional separator, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00,5Z" },
-      false,
-    ],
-    [
-      "comma fractional separator, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00,5Z" },
-      false,
-    ],
-    // Fail-closed: subject must be an RFC3339 string, target must be an epoch-ms number.
-    [
-      "numeric subject, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: JUL16_MS },
-      false,
-    ],
-    [
-      "negative epoch-ms target resolves to -1s",
-      datetimeRule("signup", "=", -1500),
-      { signup: "1969-12-31T23:59:59Z" },
-      true,
-    ],
-    [
-      "negative epoch-ms target, not equal",
-      datetimeRule("signup", "!=", -1500),
-      { signup: "1969-12-31T23:59:59Z" },
-      false,
-    ],
-    [
-      "negative epoch-ms target, at or after",
-      datetimeRule("signup", ">=", -1500),
-      { signup: "1969-12-31T23:59:59Z" },
-      true,
-    ],
-    [
-      "negative epoch-ms target, before",
-      datetimeRule("signup", "<", -1500),
-      { signup: "1969-12-31T23:59:58Z" },
-      true,
-    ],
-    [
-      "negative epoch-ms target, after",
-      datetimeRule("signup", ">", -2500),
-      { signup: "1969-12-31T23:59:59Z" },
-      true,
-    ],
-    [
-      "subject floors, it does not truncate",
-      datetimeRule("signup", "=", -2000),
-      { signup: "1969-12-31T23:59:58.500Z" },
-      true,
-    ],
-    [
-      "subject floors, not to -1s",
-      datetimeRule("signup", "!=", -1000),
-      { signup: "1969-12-31T23:59:58.500Z" },
-      true,
-    ],
-    [
-      "target beyond representable range, no match",
-      { datetime_compare: [varNode("signup"), "=", 1e308] },
-      { signup: "2026-07-16T00:00:00Z" },
-      false,
-    ],
-    [
-      "target beyond representable range, greater-than also false",
-      { datetime_compare: [varNode("signup"), ">", 1e308] },
-      { signup: "2026-07-16T00:00:00Z" },
-      false,
-    ],
-    [
-      "target beyond representable range, less-than also false",
-      { datetime_compare: [varNode("signup"), "<", 1e308] },
-      { signup: "2026-07-16T00:00:00Z" },
-      false,
-    ],
-    [
-      "bare date subject, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16" },
-      false,
-    ],
-    [
-      "bare date subject, not-equal also false",
-      datetimeRule("signup", "!=", JUL16_MS),
-      { signup: "2026-07-16" },
-      false,
-    ],
-    [
-      "zoneless datetime subject, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "2026-07-16T00:00:00" },
-      false,
-    ],
-    [
-      "non-datetime string, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      { signup: "yesterday" },
-      false,
-    ],
-    [
-      "missing property, no match",
-      datetimeRule("signup", "=", JUL16_MS),
-      {},
-      false,
-    ],
-    [
-      "missing operand, no match",
-      { datetime_compare: [varNode("signup"), "="] },
-      { signup: "2026-07-16T00:00:00Z" },
-      false,
-    ],
-  ])("%s", (_name, rule, data, want) => {
+  it.each(loadVectors("datetime"))("%s", (_name, rule, data, want) => {
     expect(apply(rule, data)).toBe(want);
   });
 });
+
+// The cases below are not golden vectors. They pin behaviour the shared files cannot express: a
+// rule shape the engine would never produce, and the difference between an absent property and one
+// holding a null, which both fail closed.
+describe("fail-closed guards", () => {
+  it("refuses a rule that is missing an operand", () => {
+    const rule = { datetime_compare: [{ var: "signup" }, "==="] };
+    expect(apply(rule, { signup: "2026-07-16T00:00:00Z" })).toBe(false);
+  });
+
+  it("omits the property for an unset subject", () => {
+    expect(dataFor(null)).toEqual({});
+    expect(dataFor("1.2.3")).toEqual({ [VECTOR_KEY]: "1.2.3" });
+  });
+});
diff --git a/packages/mixpanel/test/flags/test-data/datetime_compare_tests.json b/packages/mixpanel/test/flags/test-data/datetime_compare_tests.json
new file mode 100644
index 0000000..48fb8f5
--- /dev/null
+++ b/packages/mixpanel/test/flags/test-data/datetime_compare_tests.json
@@ -0,0 +1,89 @@
+[
+  "A list of golden vectors for custom operators, to ensure logic parity across platforms",
+
+  "# Ordering and the six symbols",
+  ["2026-07-15T00:00:00Z", "<", 1784160000000, true],
+  ["2026-07-16T00:00:00Z", "<", 1784160000000, false],
+  ["2026-07-16T00:00:00Z", "===", 1784160000000, true],
+  ["2026-07-17T00:00:00Z", "!==", 1784160000000, true],
+  ["2026-07-16T00:00:00Z", ">=", 1784160000000, true],
+  ["2026-07-17T00:00:00Z", ">", 1784160000000, true],
+  ["2026-07-15T00:00:00Z", ">", 1784160000000, false],
+  ["2026-07-16T00:00:00Z", "<=", 1784160000000, true],
+  ["2026-07-17T00:00:00Z", "<=", 1784160000000, false],
+  ["2026-07-17T00:00:00Z", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00Z", "!==", 1784160000000, false],
+  ["2026-07-15T00:00:00Z", ">=", 1784160000000, false],
+
+  "# Leap day",
+  ["2024-02-29T00:00:00Z", "===", 1709164800000, true],
+
+  "# Time-zone offsets change the instant",
+  ["2026-07-16T00:00:00+05:30", "===", 1784140200000, true],
+  ["2026-07-16T02:00:00+02:00", "===", 1784160000000, true],
+  ["2026-07-16T00:00:00+05:30", "<", 1784160000000, true],
+  ["2026-07-16T00:00:00-08:00", "===", 1784188800000, true],
+  ["2026-07-16T00:00:00-08:00", ">", 1784160000000, true],
+  ["2026-07-16T00:00:00+00:00", "===", 1784160000000, true],
+
+  "# Sub-second precision is dropped",
+  ["2026-07-16T00:00:00.5Z", "===", 1784160000000, true],
+  ["2026-07-16T00:00:00.500Z", "===", 1784160000000, true],
+  ["2026-07-16T00:00:00.123456Z", "===", 1784160000000, true],
+  ["2026-07-16T00:00:00.999999999Z", "===", 1784160000000, true],
+  ["2026-07-16T00:00:00.0Z", "===", 1784160000000, true],
+  ["2026-07-16T00:00:00.500Z", ">=", 1784160000000, true],
+  ["2026-07-16T23:59:59Z", "===", 1784246399999, true],
+  ["2026-07-16T23:59:59Z", "<=", 1784246399999, true],
+  ["2026-07-16T23:59:59.999Z", "===", 1784246399999, true],
+  ["2026-07-16T23:59:59.999Z", "<=", 1784246399999, true],
+
+  "# Trimming and lowercasing",
+  ["2026-07-16t00:00:00.500z", "===", 1784160000000, true],
+  ["2026-07-16t02:00:00+02:00", "===", 1784160000000, true],
+  [" 2026-07-16T00:00:00Z ", "===", 1784160000000, true],
+  ["2026-07-16t00:00:00z", "===", 1784160000000, true],
+
+  "# Wrong shapes, checked under both symbols",
+  ["2026-7-16T00:00:00Z", "===", 1784160000000, false],
+  ["2026-7-16T00:00:00Z", "!==", 1784160000000, false],
+  ["2026-07-16 00:00:00Z", "===", 1784160000000, false],
+  ["2026-07-16 00:00:00Z", "!==", 1784160000000, false],
+  ["2026-07-16T00:00:00", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00", "!==", 1784160000000, false],
+  ["2026-07-16T00:00:00.Z", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00.Z", "!==", 1784160000000, false],
+  ["2026-07-16T00:00:00+0200", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00+0200", "!==", 1784160000000, false],
+  ["2026-07-16T00:00:00+02", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00+02", "!==", 1784160000000, false],
+  ["2026-07-16T00:00:00Zextra", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00Zextra", "!==", 1784160000000, false],
+  ["2026-07-16", "===", 1784160000000, false],
+  ["2026-07-16", "!==", 1784160000000, false],
+  ["20260716T000000Z", "===", 1784160000000, false],
+  ["20260716T000000Z", "!==", 1784160000000, false],
+  ["2026-07-16T00:00:00z00:00", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00z00:00", "!==", 1784160000000, false],
+  ["2026-07-16T00:00:00,5Z", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00,5Z", "!==", 1784160000000, false],
+
+  "# Missing or wrong-typed values",
+  [1784160000000, "===", 1784160000000, false],
+  ["2026-07-16T00:00:00Z", "===", 1e308, false],
+  ["2026-07-16T00:00:00Z", ">", 1e308, false],
+  ["2026-07-16T00:00:00Z", "<", 1e308, false],
+  ["2026-07-16", "===", 1784160000000, false],
+  ["2026-07-16T00:00:00", "===", 1784160000000, false],
+  ["yesterday", "===", 1784160000000, false],
+  [null, "===", 1784160000000, false],
+
+  "# Targets before 1970",
+  ["1969-12-31T23:59:59Z", "===", -1500, true],
+  ["1969-12-31T23:59:59Z", "!==", -1500, false],
+  ["1969-12-31T23:59:59Z", ">=", -1500, true],
+  ["1969-12-31T23:59:58Z", "<", -1500, true],
+  ["1969-12-31T23:59:59Z", ">", -2500, true],
+  ["1969-12-31T23:59:58.500Z", "===", -2000, true],
+  ["1969-12-31T23:59:58.500Z", "!==", -1000, true]
+]
diff --git a/packages/mixpanel/test/flags/test-data/semver_compare_tests.json b/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
new file mode 100644
index 0000000..9054963
--- /dev/null
+++ b/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
@@ -0,0 +1,155 @@
+[
+  "A list of golden vectors for custom operators, to ensure logic parity across platforms",
+
+  "# Ordering and the six symbols",
+  ["1.2.3", "===", "1.2.3", true],
+  ["1.2.4", "===", "1.2.3", false],
+  ["1.2.4", "!==", "1.2.3", true],
+  ["1.2.2", "<", "1.2.3", true],
+  ["1.2.3", "<", "1.2.3", false],
+  ["1.2.3", "<=", "1.2.3", true],
+  ["1.3.0", ">", "1.2.3", true],
+  ["1.2.3", ">=", "1.2.3", true],
+  ["1.10.0", ">", "1.9.0", true],
+  ["10.0.0", ">", "9.0.0", true],
+  ["1.0.10", ">", "1.0.9", true],
+  ["2.0.0", ">", "1.9.9", true],
+  ["1.0.0-alpha", "<", "1.0.0", true],
+  ["v1.2.3", "===", "1.2.3", true],
+  ["1.2.0", "===", "1.2", true],
+  [" 1.2.3 ", "===", "1.2.3", true],
+  ["1.2.3", "!==", "1.2.3", false],
+  ["1.2.4", "<=", "1.2.3", false],
+  ["1.2.2", ">", "1.2.3", false],
+  ["1.2.2", ">=", "1.2.3", false],
+
+  "# Pre-release ordering",
+  ["1.0.0-alpha", "<", "1.0.0-beta", true],
+  ["1.0.0-beta", "<", "1.0.0-rc1", true],
+  ["1.0.0-rc1", "<", "1.0.0-rc2", true],
+  ["1.0.0-alpha", "<", "1.0.0-alpha.1", true],
+  ["1.0.0-alpha.1", "<", "1.0.0-alpha.beta", true],
+  ["1.0.0-alpha", "<", "1.0.0-alpha.beta", true],
+  ["1.0.0-beta.2", "<", "1.0.0-beta.11", true],
+  ["1.0.0-a.1", "<", "1.0.0-b.1", true],
+  ["1.0.0-a.1", "<", "1.0.0-a.2", true],
+  ["1.0.0-rc1", "===", "1.0.0-rc1", true],
+  ["1.0.0-rc1", ">", "1.0.0-rc.1", true],
+  ["2.0.0-alpha", ">", "1.9.9", true],
+
+  "# A pre-release and a plain release, compared directly",
+  ["1.0.0", ">", "1.0.0-alpha", true],
+  ["1.0.0", ">=", "1.0.0-rc1", true],
+  ["1.0.0", "!==", "1.0.0-alpha", true],
+  ["1.0.0-alpha", "!==", "1.0.0", true],
+  ["1.0.0-alpha", "<=", "1.0.0", true],
+  ["1.0.0-alpha", ">", "0.9.9", true],
+  ["1.0.0-rc1", "<", "1.0.1", true],
+
+  "# How pre-release identifiers compare, SemVer 2.0.0 item 11",
+  ["1.0.0-2", "<", "1.0.0-10", true],
+  ["1.0.0-1", "<", "1.0.0-alpha", true],
+  ["1.0.0-alpha", "<", "1.0.0-alpha-1", true],
+  ["1.0.0-beta.11", "<", "1.0.0-rc.1", true],
+  ["1.0.0-rc.1", "<", "1.0.0", true],
+  ["1.0.0-alpha.1.2.3", "<", "1.0.0-beta", true],
+  ["1.0.0-beta", ">", "1.0.0-alpha.1", true],
+
+  "# Build metadata is ignored",
+  ["1.0.0+build1", "===", "1.0.0+build2", true],
+  ["1.0.0-alpha+build", "===", "1.0.0-alpha", true],
+  ["1.2.3+build.1-2", "===", "1.2.3", true],
+  ["1.0.0+build1", "!==", "1.0.0+build2", false],
+  ["1.0.0+build1", "<", "1.0.0+build2", false],
+  ["1.0.0+build1", ">", "1.0.0+build2", false],
+  ["1.0.0+build1", "<=", "1.0.0+build2", true],
+  ["1.0.0+build1", ">=", "1.0.0+build2", true],
+  ["1.0.0+build9", "<", "1.0.1+build1", true],
+  ["1.0.1+build1", ">", "1.0.0+build9", true],
+
+  "# Partial versions",
+  ["1.2-alpha", "===", "1.2.0-alpha", true],
+  ["1.2-alpha", "<", "1.3.1", true],
+  ["1.2-alpha", "<", "1.2.0", true],
+  ["1-rc1", "<", "1.0.0", true],
+  ["1.2+build", "===", "1.2.0", true],
+
+  "# Zero versions",
+  ["0.0.0", "===", "0.0.0", true],
+  ["0.0.0", "<", "0.0.1", true],
+  ["0", "===", "0.0.0", true],
+
+  "# A version ending in a bare hyphen is rejected",
+  ["1.0.0-", "===", "1.0.0", false],
+  ["1.0.0-", "!==", "1.0.0", false],
+  ["1.2-", "===", "1.2.0", false],
+  ["1.2-", "!==", "1.2.0", false],
+
+  "# Hyphens inside a pre-release are fine, since they are part of the pre-release identifier",
+  ["1.0.0-alpha-", "<", "1.0.0", true],
+
+  "# Leading zeros are rejected",
+  ["01.2.3", "===", "1.2.3", false],
+  ["01.2.3", "!==", "1.2.3", false],
+  ["1.02.3", "===", "1.2.3", false],
+  ["1.02.3", "!==", "1.2.3", false],
+  ["1.2.03", "===", "1.2.3", false],
+  ["1.2.03", "!==", "1.2.3", false],
+  ["01.02.03", "===", "1.2.3", false],
+  ["01.02.03", "!==", "1.2.3", false],
+
+  "# Leading zeros in a numeric pre-release are rejected too, SemVer 2.0.0 item 9",
+  ["1.2.3-01", "===", "1.2.3", false],
+  ["1.2.3-01", "!==", "1.2.3", false],
+  ["1.2.3-rc.01", "===", "1.2.3", false],
+  ["1.2.3-rc.01", "!==", "1.2.3", false],
+
+  "# A lone zero is a legal pre-release identifier",
+  ["1.2.3-0", "<", "1.2.3", true],
+
+  "# Digits inside a word are still valid",
+  ["1.2.3-rc01", "<", "1.2.3", true],
+
+  "# A leading v is accepted, in either case",
+  ["V1.2.3", "===", "1.2.3", true],
+  ["v1.0.0-alpha", "<", "1.0.0", true],
+  ["v1.2.4", "!==", "1.2.3", true],
+  ["v1.2.3", "<=", "1.2.3", true],
+  ["v1.2.4", ">", "1.2.3", true],
+  ["v1.2.3", ">=", "1.2.3", true],
+
+  "# Missing or wrong-typed values",
+  ["not-a-version", "===", "1.2.3", false],
+  [123, "===", "1.2.3", false],
+  [null, "===", "1.2.3", false],
+
+  "# Malformed versions, checked under both symbols",
+  ["", "===", "1.2.3", false],
+  ["", "!==", "1.2.3", false],
+  ["v", "===", "1.2.3", false],
+  ["v", "!==", "1.2.3", false],
+  ["-1.2.3", "===", "1.2.3", false],
+  ["-1.2.3", "!==", "1.2.3", false],
+  ["1.", "===", "1.2.3", false],
+  ["1.", "!==", "1.2.3", false],
+  ["1.2.3.", "===", "1.2.3", false],
+  ["1.2.3.", "!==", "1.2.3", false],
+  ["1..2", "===", "1.2.3", false],
+  ["1..2", "!==", "1.2.3", false],
+  ["1.2.3.4", "===", "1.2.3", false],
+  ["1.2.3.4", "!==", "1.2.3", false],
+  ["^1.2.3", "===", "1.2.3", false],
+  ["^1.2.3", "!==", "1.2.3", false],
+  ["abc1.2.3", "===", "1.2.3", false],
+  ["abc1.2.3", "!==", "1.2.3", false],
+  ["1.2.3+", "===", "1.2.3", false],
+  ["1.2.3+", "!==", "1.2.3", false],
+  ["1.2.3-alpha..1", "===", "1.2.3", false],
+  ["1.2.3-alpha..1", "!==", "1.2.3", false],
+  ["1.2.3-.", "===", "1.2.3", false],
+  ["1.2.3-.", "!==", "1.2.3", false],
+  ["1.2.3-ALPHA_BETA", "===", "1.2.3", false],
+  ["1.2.3-ALPHA_BETA", "!==", "1.2.3", false],
+  ["vv1.2.3", "===", "1.2.3", false],
+  ["vv1.2.3", "!==", "1.2.3", false]
+]

From aaaa49c5edaacf0d38bb5079861d5d7644dbde2d Mon Sep 17 00:00:00 2001
From: Kwame Efah <37164746+efahk@users.noreply.github.com>
Date: Tue, 25 Aug 2026 23:00:58 +0000
Subject: [PATCH 4/7] updating tests and adding semver limits

---
 .../mixpanel/lib/flags/custom_operators.js    | 41 +++++++++++++++++--
 .../test-data/datetime_compare_tests.json     | 37 +++++++++++------
 .../flags/test-data/semver_compare_tests.json |  8 +++-
 3 files changed, 69 insertions(+), 17 deletions(-)

diff --git a/packages/mixpanel/lib/flags/custom_operators.js b/packages/mixpanel/lib/flags/custom_operators.js
index 7089b8d..dcc8532 100644
--- a/packages/mixpanel/lib/flags/custom_operators.js
+++ b/packages/mixpanel/lib/flags/custom_operators.js
@@ -1,12 +1,18 @@
 const jsonLogic = require("json-logic-js");
 
-// Strict RFC3339 guard for datetime strings.
+// Strict RFC3339 guard for datetime strings. The date and hour fields are captured so the calendar
+// can be validated separately; the pattern only constrains their shape.
 const RFC3339_PATTERN =
-  /^\d{4}-\d{2}-\d{2}[Tt]\d{2}:\d{2}:\d{2}(\.\d+)?([Zz]|[+-]\d{2}:\d{2})$/;
+  /^(\d{4})-(\d{2})-(\d{2})[Tt](\d{2}):\d{2}:\d{2}(\.\d+)?([Zz]|[+-]\d{2}:\d{2})$/;
 
 // SemVer 2.0.0 requires major.minor.patch; partial versions are zero-padded to this.
 const SEMVER_PARTS = 3;
 
+// Longest operand the semver regex is allowed to see. A real version never approaches this; the
+// bound matches MAX_LENGTH in node-semver, and keeps an arbitrarily long property value off the
+// regex regardless of how the engine schedules backtracking.
+const MAX_SEMVER_LENGTH = 256;
+
 // Epoch milliseconds are compared as int64 elsewhere, so anything at or beyond this is out of range.
 const MAX_EPOCH_MS = 9223372036854775808;
 
@@ -28,6 +34,9 @@ function semverCompare(actual, symbol, target) {
   if (typeof actual !== "string" || typeof target !== "string") {
     return false;
   }
+  if (actual.length > MAX_SEMVER_LENGTH || target.length > MAX_SEMVER_LENGTH) {
+    return false;
+  }
   const actualVersion = normalizeSemver(actual);
   const targetVersion = normalizeSemver(target);
   if (
@@ -184,12 +193,38 @@ function normalizeSemver(version) {
   return parts.join(".") + suffix;
 }
 
+function daysInMonth(year, month) {
+  if (month === 2) {
+    const isLeapYear = (year % 4 === 0 && year % 100 !== 0) || year % 400 === 0;
+    return isLeapYear ? 29 : 28;
+  }
+  return month === 4 || month === 6 || month === 9 || month === 11 ? 30 : 31;
+}
+
+// The pattern constrains each field to two digits, which still admits a date that cannot exist, such
+// as 2026-02-30 or 29 February in a common year. Date.parse rolls those forward into a real instant
+// instead of rejecting them, and hour 24 likewise becomes the following midnight, so the calendar is
+// checked here rather than left to the engine. RFC 3339 section 5.6 allows hours 00 through 23.
+function isRealCalendarDate(year, month, day, hour) {
+  if (month < 1 || month > 12 || day < 1 || hour > 23) {
+    return false;
+  }
+  return day <= daysInMonth(year, month);
+}
+
 function convertRfc3339ToUnixSeconds(value) {
   if (typeof value !== "string") {
     return null;
   }
   const normalized = value.trim().toUpperCase();
-  if (!RFC3339_PATTERN.test(normalized)) {
+  const fields = RFC3339_PATTERN.exec(normalized);
+  if (!fields) {
+    return null;
+  }
+  const [, year, month, day, hour] = fields;
+  if (
+    !isRealCalendarDate(Number(year), Number(month), Number(day), Number(hour))
+  ) {
     return null;
   }
   const ms = Date.parse(normalized);
diff --git a/packages/mixpanel/test/flags/test-data/datetime_compare_tests.json b/packages/mixpanel/test/flags/test-data/datetime_compare_tests.json
index 48fb8f5..5e8633d 100644
--- a/packages/mixpanel/test/flags/test-data/datetime_compare_tests.json
+++ b/packages/mixpanel/test/flags/test-data/datetime_compare_tests.json
@@ -33,10 +33,10 @@
   ["2026-07-16T00:00:00.999999999Z", "===", 1784160000000, true],
   ["2026-07-16T00:00:00.0Z", "===", 1784160000000, true],
   ["2026-07-16T00:00:00.500Z", ">=", 1784160000000, true],
-  ["2026-07-16T23:59:59Z", "===", 1784246399999, true],
-  ["2026-07-16T23:59:59Z", "<=", 1784246399999, true],
-  ["2026-07-16T23:59:59.999Z", "===", 1784246399999, true],
-  ["2026-07-16T23:59:59.999Z", "<=", 1784246399999, true],
+  ["2026-07-16T23:59:59Z", "===", 1784246399000, true],
+  ["2026-07-16T23:59:59Z", "<=", 1784246399000, true],
+  ["2026-07-16T23:59:59.999Z", "===", 1784246399000, true],
+  ["2026-07-16T23:59:59.999Z", "<=", 1784246399000, true],
 
   "# Trimming and lowercasing",
   ["2026-07-16t00:00:00.500z", "===", 1784160000000, true],
@@ -70,20 +70,31 @@
 
   "# Missing or wrong-typed values",
   [1784160000000, "===", 1784160000000, false],
-  ["2026-07-16T00:00:00Z", "===", 1e308, false],
-  ["2026-07-16T00:00:00Z", ">", 1e308, false],
-  ["2026-07-16T00:00:00Z", "<", 1e308, false],
+  ["2026-07-16T00:00:00Z", "===", 1e19, false],
+  ["2026-07-16T00:00:00Z", ">", 1e19, false],
+  ["2026-07-16T00:00:00Z", "<", 1e19, false],
   ["2026-07-16", "===", 1784160000000, false],
   ["2026-07-16T00:00:00", "===", 1784160000000, false],
   ["yesterday", "===", 1784160000000, false],
   [null, "===", 1784160000000, false],
 
   "# Targets before 1970",
-  ["1969-12-31T23:59:59Z", "===", -1500, true],
-  ["1969-12-31T23:59:59Z", "!==", -1500, false],
-  ["1969-12-31T23:59:59Z", ">=", -1500, true],
-  ["1969-12-31T23:59:58Z", "<", -1500, true],
-  ["1969-12-31T23:59:59Z", ">", -2500, true],
+  ["1969-12-31T23:59:59Z", "===", -1000, true],
+  ["1969-12-31T23:59:59Z", "!==", -1000, false],
+  ["1969-12-31T23:59:59Z", ">=", -1000, true],
+  ["1969-12-31T23:59:58Z", "<", -1000, true],
+  ["1969-12-31T23:59:59Z", ">", -2000, true],
   ["1969-12-31T23:59:58.500Z", "===", -2000, true],
-  ["1969-12-31T23:59:58.500Z", "!==", -1000, true]
+  ["1969-12-31T23:59:58.500Z", "!==", -1000, true],
+
+  "# Impossible dates and out-of-range fields",
+  ["2026-02-30T00:00:00Z", "===", 1784160000000, false],
+  ["2026-02-30T00:00:00Z", "!==", 1784160000000, false],
+  ["2026-02-29T00:00:00Z", "!==", 1784160000000, false],
+  ["2025-02-29T00:00:00Z", "!==", 1784160000000, false],
+  ["2026-04-31T00:00:00Z", "!==", 1784160000000, false],
+  ["2026-06-31T00:00:00Z", "!==", 1784160000000, false],
+  ["2026-07-16T24:00:00Z", "!==", 1784160000000, false],
+  ["2026-13-01T00:00:00Z", "!==", 1784160000000, false],
+  ["2026-01-32T00:00:00Z", "!==", 1784160000000, false]
 ]
diff --git a/packages/mixpanel/test/flags/test-data/semver_compare_tests.json b/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
index 9054963..42c6c75 100644
--- a/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
+++ b/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
@@ -151,5 +151,11 @@
   ["1.2.3-ALPHA_BETA", "===", "1.2.3", false],
   ["1.2.3-ALPHA_BETA", "!==", "1.2.3", false],
   ["vv1.2.3", "===", "1.2.3", false],
-  ["vv1.2.3", "!==", "1.2.3", false]
+  ["vv1.2.3", "!==", "1.2.3", false],
+
+  "# Operand length cap",
+  ["1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "===", "1.2.3", false],
+  ["1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "!==", "1.2.3", false],
+  ["1.2.3", "!==", "1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", false],
+  ["1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "!==", "1.2.3", true]
 ]

From d53241901c1de2a47bfe107897a8c5a91d36c2cc Mon Sep 17 00:00:00 2001
From: Kwame Efah <37164746+efahk@users.noreply.github.com>
Date: Tue, 25 Aug 2026 23:23:23 +0000
Subject: [PATCH 5/7] lint and fixing lock file

---
 package-lock.json                             |  7 -----
 .../flags/test-data/semver_compare_tests.json | 28 ++++++++++++++++---
 2 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 746f256..b13940e 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1060,12 +1060,6 @@
         "node": ">=18"
       }
     },
-    "node_modules/compare-versions": {
-      "version": "6.1.1",
-      "resolved": "https://registry.npmjs.org/compare-versions/-/compare-versions-6.1.1.tgz",
-      "integrity": "sha512-4hm4VPpIecmlg59CHXnRDnqGplJFrbLG4aFEl5vl6cK1u76ws3LLvX7ikFnTDl5vo39sjWD6AaDPYodJp/NNHg==",
-      "license": "MIT"
-    },
     "node_modules/convert-source-map": {
       "version": "2.0.0",
       "resolved": "https://registry.npmjs.org/convert-source-map/-/convert-source-map-2.0.0.tgz",
@@ -2248,7 +2242,6 @@
       "version": "0.23.0",
       "license": "MIT",
       "dependencies": {
-        "compare-versions": "6.1.1",
         "https-proxy-agent": "7.0.6",
         "json-logic-js": "2.0.5"
       },
diff --git a/packages/mixpanel/test/flags/test-data/semver_compare_tests.json b/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
index 42c6c75..ae475e6 100644
--- a/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
+++ b/packages/mixpanel/test/flags/test-data/semver_compare_tests.json
@@ -154,8 +154,28 @@
   ["vv1.2.3", "!==", "1.2.3", false],
 
   "# Operand length cap",
-  ["1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "===", "1.2.3", false],
-  ["1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "!==", "1.2.3", false],
-  ["1.2.3", "!==", "1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", false],
-  ["1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa", "!==", "1.2.3", true]
+  [
+    "1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    "===",
+    "1.2.3",
+    false
+  ],
+  [
+    "1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    "!==",
+    "1.2.3",
+    false
+  ],
+  [
+    "1.2.3",
+    "!==",
+    "1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    false
+  ],
+  [
+    "1.2.3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa",
+    "!==",
+    "1.2.3",
+    true
+  ]
 ]

From 0b28f18720587967e684964c3ef3e2928ffd504f Mon Sep 17 00:00:00 2001
From: Kwame Efah <37164746+efahk@users.noreply.github.com>
Date: Wed, 26 Aug 2026 18:32:12 +0000
Subject: [PATCH 6/7] simplifying date check

---
 .../mixpanel/lib/flags/custom_operators.js    | 23 ++++++++-----------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/packages/mixpanel/lib/flags/custom_operators.js b/packages/mixpanel/lib/flags/custom_operators.js
index dcc8532..00f597c 100644
--- a/packages/mixpanel/lib/flags/custom_operators.js
+++ b/packages/mixpanel/lib/flags/custom_operators.js
@@ -193,23 +193,20 @@ function normalizeSemver(version) {
   return parts.join(".") + suffix;
 }
 
-function daysInMonth(year, month) {
-  if (month === 2) {
-    const isLeapYear = (year % 4 === 0 && year % 100 !== 0) || year % 400 === 0;
-    return isLeapYear ? 29 : 28;
-  }
-  return month === 4 || month === 6 || month === 9 || month === 11 ? 30 : 31;
-}
-
 // The pattern constrains each field to two digits, which still admits a date that cannot exist, such
-// as 2026-02-30 or 29 February in a common year. Date.parse rolls those forward into a real instant
-// instead of rejecting them, and hour 24 likewise becomes the following midnight, so the calendar is
-// checked here rather than left to the engine. RFC 3339 section 5.6 allows hours 00 through 23.
+// as 2026-02-30 or 29 February in a common year. Writing the fields into a Date and reading them back
+// settles it: out-of-range fields are normalized into a real instant, so a date that does not exist
+// comes back carrying different fields than it went in with. The three-argument setUTCFullYear sets
+// all three at once, which judges 29 February against the year given rather than a placeholder, and
+// leaves years 0 through 99 alone where Date.UTC would map them into the 1900s. The hour is checked
+// separately because it is not part of the round trip; RFC 3339 section 5.6 allows hours 00 through 23.
 function isRealCalendarDate(year, month, day, hour) {
-  if (month < 1 || month > 12 || day < 1 || hour > 23) {
+  if (hour > 23) {
     return false;
   }
-  return day <= daysInMonth(year, month);
+  const dt = new Date();
+  dt.setUTCFullYear(year, month - 1, day);
+  return dt.getUTCFullYear() === year && dt.getUTCMonth() === month - 1 && dt.getUTCDate() === day;
 }
 
 function convertRfc3339ToUnixSeconds(value) {

From 2327e710118884aedd4c9a0f646ab6bdc8d09d0e Mon Sep 17 00:00:00 2001
From: Kwame Efah <37164746+efahk@users.noreply.github.com>
Date: Wed, 26 Aug 2026 20:52:28 +0000
Subject: [PATCH 7/7] lint

---
 packages/mixpanel/lib/flags/custom_operators.js | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/packages/mixpanel/lib/flags/custom_operators.js b/packages/mixpanel/lib/flags/custom_operators.js
index 00f597c..061ff82 100644
--- a/packages/mixpanel/lib/flags/custom_operators.js
+++ b/packages/mixpanel/lib/flags/custom_operators.js
@@ -206,7 +206,11 @@ function isRealCalendarDate(year, month, day, hour) {
   }
   const dt = new Date();
   dt.setUTCFullYear(year, month - 1, day);
-  return dt.getUTCFullYear() === year && dt.getUTCMonth() === month - 1 && dt.getUTCDate() === day;
+  return (
+    dt.getUTCFullYear() === year &&
+    dt.getUTCMonth() === month - 1 &&
+    dt.getUTCDate() === day
+  );
 }
 
 function convertRfc3339ToUnixSeconds(value) {