feat(codemode): expand standard library parity (#37943)

packages/codemode/test/array-core-test262.test.ts

@@ -29,6 +29,11 @@
  * - test/built-ins/Array/prototype/splice/S15.4.4.12_A1.1_T1.js
  * - test/built-ins/Array/prototype/splice/S15.4.4.12_A1.2_T1.js
  * - test/built-ins/Array/prototype/splice/called_with_one_argument.js
+ * - test/built-ins/Array/prototype/toSpliced/holes-not-preserved.js
+ * - test/built-ins/Array/prototype/toSpliced/immutable.js
+ * - test/built-ins/Array/prototype/toSpliced/start-and-deleteCount-undefineds.js
+ * - test/built-ins/Array/prototype/toSpliced/start-and-deleteCount-missing.js
+ * - test/built-ins/Array/prototype/toSpliced/start-undefined-and-deleteCount-missing.js
  * - test/built-ins/Array/prototype/fill/fill-values.js
  * - test/built-ins/Array/prototype/fill/fill-values-custom-start-and-end.js
  * - test/built-ins/Array/prototype/fill/return-this.js
@@ -59,6 +64,8 @@
  * Copyright 2015 Microsoft Corporation. All rights reserved.
  * Copyright 2016 The V8 project authors. All rights reserved.
  * Test262 portions are governed by the BSD license in LICENSE.test262.
+ * The toSpliced hole case omits the source test's inherited Array.prototype element because CodeMode does not expose
+ * prototype mutation; it retains the source test's hole-densification assertions.
  */
 import { describe, expect, test } from "bun:test"
 import { Effect } from "effect"
@@ -227,6 +234,31 @@ const cases = [
     code: `const input = ["first", "second", "third"]; const removed = input.splice(1); return [input, removed]`,
     expected: [["first"], ["second", "third"]],
   },
+  {
+    path: "test/built-ins/Array/prototype/toSpliced/immutable.js",
+    code: `const input = [2, 0, 1]; const inserted = input.toSpliced(0, 0, -1); const replaced = input.toSpliced(0, 1, -1); return [input, inserted, replaced, inserted !== input, replaced !== input]`,
+    expected: [[2, 0, 1], [-1, 2, 0, 1], [-1, 0, 1], true, true],
+  },
+  {
+    path: "test/built-ins/Array/prototype/toSpliced/start-and-deleteCount-missing.js",
+    code: `const input = ["first", "second", "third"]; const result = input.toSpliced(); return [result, result !== input]`,
+    expected: [["first", "second", "third"], true],
+  },
+  {
+    path: "test/built-ins/Array/prototype/toSpliced/start-undefined-and-deleteCount-missing.js",
+    code: `return ["first", "second", "third"].toSpliced(undefined)`,
+    expected: [],
+  },
+  {
+    path: "test/built-ins/Array/prototype/toSpliced/start-and-deleteCount-undefineds.js",
+    code: `const input = ["first", "second", "third"]; const result = input.toSpliced(undefined, undefined); return [result, result !== input]`,
+    expected: [["first", "second", "third"], true],
+  },
+  {
+    path: "test/built-ins/Array/prototype/toSpliced/holes-not-preserved.js",
+    code: `const input = [0, , 2, , 4]; const result = input.toSpliced(0, 0, -1); return [result, 2 in result, 4 in result]`,
+    expected: [[-1, 0, null, 2, null, 4], true, true],
+  },
   {
     path: "test/built-ins/Array/prototype/fill/fill-values-custom-start-and-end.js",
     code: `const input = [0, 0, 0, 0, 0]; input.fill(8, -3, 4); const sparse = []; sparse[4] = 0; sparse.fill(8, 1, 3); return [[0, 0, 0].fill(8, 1, 2), input, [0, 0, 0, 0, 0].fill(8, -2, -1), [0, 0, 0, 0, 0].fill(8, -1, -3), [0 in sparse, sparse[1], sparse[2], 3 in sparse, sparse[4]]]`,

packages/codemode/test/parity.test.ts

@@ -64,7 +64,7 @@ describe("H3: array property access reads as undefined (not a throw)", () => {
   })
 
   test("unknown property reads stay undefined for methods CodeMode does not implement", async () => {
-    expect(await value(`return [1,2,3].toSpliced === undefined`)).toBe(true)
+    expect(await value(`return [1,2,3].unknownMethod === undefined`)).toBe(true)
   })
 
   test("array indexing still works", async () => {

packages/codemode/test/stdlib.test.ts

@@ -2,11 +2,16 @@
  * Portions adapted from Test262 at revision 250f204f23a9249ff204be2baec29600faae7b75:
  * - test/built-ins/Date/value-to-primitive-result-non-string-prim.js
  * - test/built-ins/Date/value-to-primitive-result-string.js
+ * - test/built-ins/Date/prototype/toUTCString/format.js
+ * - test/built-ins/Date/prototype/toUTCString/invalid-date.js
+ * - test/built-ins/RegExp/prototype/exec/S15.10.6.2_A4_T8.js
  *
- * CodeMode does not support Symbol.toPrimitive, so these cases exercise the same Date-constructor primitive-result
+ * CodeMode does not support Symbol.toPrimitive, so the Date-constructor cases exercise the same primitive-result
  * handling through supported own valueOf and toString functions.
  *
  * Copyright (C) 2016 the V8 project authors. All rights reserved.
+ * Copyright (C) 2017 the V8 project authors. All rights reserved.
+ * Copyright 2009 the Sputnik authors. All rights reserved.
  * Test262 portions are governed by the BSD license in LICENSE.test262.
  */
 import { describe, expect, test } from "bun:test"
@@ -175,6 +180,25 @@ describe("Date", () => {
     expect(await value(`return typeof new Date(0)`)).toBe("object")
     expect(await value(`return new Date(0).nope === undefined`)).toBe(true)
   })
+
+  test("toUTCString and toGMTString use the native UTC format", async () => {
+    expect(
+      await value(`
+        const date = new Date(0)
+        return [
+          date.toUTCString(),
+          date.toGMTString(),
+          new Date(NaN).toUTCString(),
+          new Date("0020-01-01T00:00:00Z").toUTCString(),
+        ]
+      `),
+    ).toEqual([
+      "Thu, 01 Jan 1970 00:00:00 GMT",
+      "Thu, 01 Jan 1970 00:00:00 GMT",
+      "Invalid Date",
+      "Wed, 01 Jan 0020 00:00:00 GMT",
+    ])
+  })
 })
 
 describe("RegExp", () => {
@@ -211,6 +235,51 @@ describe("RegExp", () => {
     ).toEqual(["1", "22"])
   })
 
+  test("lastIndex is writable and exec coerces its stored value", async () => {
+    expect(
+      await value(`
+        const pattern = /(?:ab|cd)\\d?/g
+        pattern.lastIndex = "12"
+        const stored = [pattern.lastIndex, typeof pattern.lastIndex]
+        const match = pattern.exec("aacd2233ab12nm444ab42")
+        pattern.lastIndex = 0
+        return [stored, match[0], match.index, pattern.lastIndex, delete pattern.lastIndex]
+      `),
+    ).toEqual([["12", "string"], "ab4", 17, 0, false])
+  })
+
+  test("exec coerces CodeMode data objects assigned to lastIndex", async () => {
+    expect(
+      await value(`
+        const pattern = /a/g
+        pattern.lastIndex = {}
+        const stored = pattern.lastIndex
+        const match = pattern.exec("ba")
+        pattern.lastIndex = 10
+        const missed = pattern.exec("a")
+        return [stored, match.index, pattern.lastIndex, missed]
+      `),
+    ).toEqual([{}, 1, 0, null])
+  })
+
+  test("non-global exec and test coerce and preserve lastIndex", async () => {
+    expect(
+      await value(`
+        const execPattern = /a/
+        const execIndex = {}
+        execPattern.lastIndex = execIndex
+        const match = execPattern.exec("ba")
+
+        const testPattern = /a/
+        const testIndex = {}
+        testPattern.lastIndex = testIndex
+        const matched = testPattern.test("ba")
+
+        return [match.index, execPattern.lastIndex === execIndex, matched, testPattern.lastIndex === testIndex]
+      `),
+    ).toEqual([1, true, true, true])
+  })
+
   test("an unmatched string pattern returns null", async () => {
     expect(await value(`return "abc".match(/\\d/)`)).toBeNull()
   })