• Changes v3.46.0...v3.47.0 (117 commits)
• JSON.parse source text access proposal :
  • Built-ins:
    • JSON.isRawJSON
    • JSON.parse
    • JSON.rawJSON
    • JSON.stringify
  • Moved to stable ES, November 2025 TC39 meeting
  • Added es. namespace modules, /es/ and /stable/ namespaces entries
  • Reworked JSON.stringify internals
• Iterator sequencing proposal:
  • Built-ins:
    • Iterator.concat
  • Moved to stable ES, November 2025 TC39 meeting
  • Added es. namespace modules, /es/ and /stable/ namespaces entries
• Joint iteration proposal:
  • Built-ins:
    • Iterator.zip
    • Iterator.zipKeyed
  • Moved to stage 3, November 2025 TC39 meeting
  • Added /actual/ namespace entries, unconditional forced replacement changed to feature detection
• Fixed increasing .size in URLSearchParams.prototype.append polyfill in IE8-
• Compat data improvements:
  • Iterator.concat marked as shipped in FF147
  • Map upsert proposal features marked as shipped in Safari 26.2
  • Math.sumPrecise marked as shipped in Safari 26.2
  • Uint8Array.{ fromBase64, prototype.setFromBase64 } marked as fixed in Safari 26.2
  • Missed Explicit Resource Management features added in Bun 1.3.0
  • Added Oculus Quest Browser 41 compat data mapping
  • Added Electron 40 compat data mapping

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• Changes v3.45.1...v3.46.0 (116 commits)
• Map upsert stage 3 proposal:
  • Fixed a FF WeakMap.prototype.getOrInsertComputed bug with callback calling before validation a key
• Iterator chunking proposal:
  • Built-ins:
    • Iterator.prototype.chunks
    • Iterator.prototype.windows
  • Moved to stage 2.7, September 2025 TC39 meeting
  • Iterator.prototype.sliding method replaced with an extra parameter of Iterator.prototype.windows method, tc39/proposal-iterator-chunking/#24, tc39/proposal-iterator-chunking/#26
• Fixed Iterator.zip and Iterator.zipKeyed behavior with mode: 'longest' option, #1469, thanks @lionel-rowe
• Fixed work of Object.groupBy and Iterator.zipKeyed together with Symbol polyfill - some cases of symbol keys on result null-prototype object were able to leak out to for-in
• Compat data improvements:
  • Map upsert proposal features marked as shipped from FF144
  • Added Node 25.0 compat data mapping
  • Added Deno 2.5 compat data mapping
  • Updated Electron 39 compat data mapping
  • Updated Opera 121+ compat data mapping
  • Added Opera Android 92 compat data mapping
  • Added Oculus Quest Browser 40 compat data mapping

• Changes v3.45.0...v3.45.1 (30 commits)
• Fixed a conflict of native methods from Map upsert proposal with polyfilled methods in the pure version
• Added bugs fields to package.json of all packages
• Compat data improvements:
  • Map upsert proposal features marked as shipped from Bun 1.2.20
  • Added Samsung Internet 29 compat data mapping
  • Added Electron 39 compat data mapping

• Changes v3.44.0...v3.45.0 (70 commits)
• Uint8Array to / from base64 and hex proposal:
  • Built-ins:
    • Uint8Array.fromBase64
    • Uint8Array.fromHex
    • Uint8Array.prototype.setFromBase64
    • Uint8Array.prototype.setFromHex
    • Uint8Array.prototype.toBase64
    • Uint8Array.prototype.toHex
  • Moved to stable ES, July 2025 TC39 meeting
  • Added es. namespace modules, /es/ and /stable/ namespaces entries
  • Added detection of a Webkit bug: Uint8Array fromBase64 / setFromBase64 does not throw an error on incorrect length of base64 string
• Math.sumPrecise proposal:
  • Built-ins:
    • Math.sumPrecise
  • Moved to stable ES, July 2025 TC39 meeting
  • Added es. namespace module, /es/ and /stable/ namespaces entries
• Iterator sequencing proposal:
  • Built-ins:
    • Iterator.concat
  • Moved to stage 3, July 2025 TC39 meeting
  • Added /actual/ namespace entries, unconditional forced replacement changed to feature detection
• Map upsert proposal:
  • Built-ins:
    • Map.prototype.getOrInsert
    • Map.prototype.getOrInsertComputed
    • WeakMap.prototype.getOrInsert
    • WeakMap.prototype.getOrInsertComputed
  • Moved to stage 3, July 2025 TC39 meeting
  • Added /actual/ namespace entries, unconditional forced replacement changed to feature detection
• Added missing dependencies to some entries of static Iterator methods
• Fixed Joint Iteration proposal in /stage/ entries
• Compat data improvements:
  • Uint8Array to / from base64 and hex proposal features marked as supported from V8 ~ Chromium 140
  • Uint8Array.{ fromBase64, prototype.setFromBase64 } marked as unsupported in Safari and supported only from Bun 1.2.20 because of a bug: it does not throw an error on incorrect length of base64 string
  • %TypedArray%.prototype.with marked as fixed in Safari 26.0
  • Updated Electron 38 compat data mapping
  • Added Opera Android 91 compat data mapping

• Changes v3.43.0...v3.44.0 (87 commits)
• Uint8Array to / from base64 and hex stage 3 proposal:
  • Fixed several V8 bugs in Uint8Array.fromHex and Uint8Array.prototype.{ setFromBase64, toBase64, toHex }, thanks @brc-dd
• Joint iteration stage 2.7 proposal:
  • Uses Get in Iterator.zipKeyed, following tc39/proposal-joint-iteration#43
• Iterator sequencing stage 2.7 proposal:
  • Iterator.concat no longer reuses IteratorResult object of concatenated iterators, following tc39/proposal-iterator-sequencing#26
• Iterator chunking stage 2 proposal:
  • Added built-ins:
    • Iterator.prototype.sliding
• Number.prototype.clamp stage 2 proposal:
  • clamp no longer throws an error on NaN as min or max, following tc39/proposal-math-clamp#d2387791c265edf66fbe2455eab919016717ce6f
• Fixed some cases of Set.prototype.{ symmetricDifference, union } detection
• Added missing dependencies to some entries of static Iterator methods
• Added missing /full/{ instance, number/virtual }/clamp entries
• Some minor stylistic changes
• Compat data improvements:
  • Added Electron 38 and 39 compat data mapping
  • Added Oculus Quest Browser 38 and 39 compat data mapping
  • Iterator helpers marked as fixed and updated following the latest spec changes in Safari 26.0
  • Set.prototype.{ difference, symmetricDifference, union } marked as fixed in Safari 26.0
  • SuppressedError marked as fixed in FF141
  • Error.isError marked as fixed in Node 24.3
  • setImmediate and clearImmediate marked as available from Deno 2.4
  • Math.sumPrecise marked as shipped in Bun 1.2.18
  • %TypedArray%.prototype.with marked as fixed in Bun 1.2.18

• Changes v3.42.0...v3.43.0 (139 commits)
• Explicit Resource Management proposals:
  • Built-ins:
    • Symbol.dispose
    • Symbol.asyncDispose
    • SuppressedError
    • DisposableStack
      • DisposableStack.prototype.dispose
      • DisposableStack.prototype.use
      • DisposableStack.prototype.adopt
      • DisposableStack.prototype.defer
      • DisposableStack.prototype.move
      • DisposableStack.prototype[@@dispose]
    • AsyncDisposableStack
      • AsyncDisposableStack.prototype.disposeAsync
      • AsyncDisposableStack.prototype.use
      • AsyncDisposableStack.prototype.adopt
      • AsyncDisposableStack.prototype.defer
      • AsyncDisposableStack.prototype.move
      • AsyncDisposableStack.prototype[@@asyncDispose]
    • Iterator.prototype[@@dispose]
    • AsyncIterator.prototype[@@asyncDispose]
  • Moved to stable ES, May 2025 TC39 meeting
  • Added es. namespace module, /es/ and /stable/ namespaces entries
• Array.fromAsync proposal:
  • Built-ins:
    • Array.fromAsync
  • Moved to stable ES, May 2025 TC39 meeting
  • Added es. namespace module, /es/ and /stable/ namespaces entries
• Error.isError proposal:
  • Built-ins:
    • Error.isError
  • Moved to stable ES, May 2025 TC39 meeting
  • Added es. namespace module, /es/ and /stable/ namespaces entries
• Added Joint iteration stage 2.7 proposal:
  • Added built-ins:
    • Iterator.zip
    • Iterator.zipKeyed
• Added Iterator chunking stage 2 proposal:
  • Added built-ins:
    • Iterator.prototype.chunks
    • Iterator.prototype.windows
• Number.prototype.clamp proposal:
  • Built-ins:
    • Number.prototype.clamp
  • Moved to stage 2, May 2025 TC39 meeting
  • Math.clamp was replaced with Number.prototype.clamp
  • Removed a RangeError if min <= max or +0 min and -0 max, tc39/proposal-math-clamp/#22
• Always check regular expression flags by flags getter PR. Native methods are not fixed, only own implementation updated for:
  • RegExp.prototype[@@match]
  • RegExp.prototype[@@replace]
• Improved handling of RegExp flags in polyfills of some methods in engines without proper support of RegExp.prototype.flags and without polyfill of this getter
• Added feature detection for a WebKit bug that occurs when this is updated while Set.prototype.difference is being executed
• Added feature detection for a WebKit bug that occurs when iterator record of a set-like object isn't called before cloning this in the following methods:
  • Set.prototype.symmetricDifference
  • Set.prototype.union
• Added feature detection for a bug in V8 ~ Chromium < 126. Following methods should throw an error on invalid iterator:
  • Iterator.prototype.drop
  • Iterator.prototype.filter
  • Iterator.prototype.flatMap
  • Iterator.prototype.map
• Added feature detection for a WebKit bug: incorrect exception thrown by Iterator.from when underlying iterator's return method is null
• Added feature detection for a FF bug: incorrect exception thrown by Array.prototype.with when index coercion fails
• Added feature detection for a WebKit bug: TypedArray.prototype.with should truncate negative fractional index to zero, but instead throws an error
• Worked around a bug of many different tools (example) with incorrect transforming and breaking JS syntax on getting a method from a number literal
• Fixed deoptimization of the Promise polyfill in the pure version
• Added some missed dependencies to /iterator/flat-map entries
• Some other minor fixes and improvements
• Compat data improvements:
  • Added Deno 2.3 and Deno 2.3.2 compat data mapping
  • Updated Electron 37 compat data mapping
  • Added Opera Android 90 compat data mapping
  • Error.isError marked not supported in Node because of a bug
  • Set.prototype.difference marked as not supported in Safari and supported only from Bun 1.2.5 because of a bug
  • Set.prototype.{ symmetricDifference, union } marked as not supported in Safari and supported only from Bun 1.2.5 because of a bug
  • Iterator.from marked as not supported in Safari and supported only from Bun 1.2.5 because of a bug
  • Iterators closing on early errors in Iterator helpers marked as implemented from FF141
  • Array.prototype.with marked as supported only from FF140 because it throws an incorrect exception when index coercion fails
  • TypedArray.prototype.with marked as unsupported in Bun and Safari because it should truncate negative fractional index to zero, but instead throws an error
  • DisposableStack and AsyncDisposableStack marked as shipped in FF141 (SuppressedError has a bug)
  • AsyncDisposableStack bugs marked as fixed in Deno 2.3.2
  • SuppressedError bugs (extra arguments support and arity) marked as fixed in Bun 1.2.15

• Changes v3.41.0...v3.42.0 (142 commits)
• Map upsert proposal:
  • Moved to stage 2.7, April 2025 TC39 meeting
  • Validation order of WeakMap.prototype.getOrInsertComputed updated following tc39/proposal-upsert#79
  • Built-ins:
    • Map.prototype.getOrInsert
    • Map.prototype.getOrInsertComputed
    • WeakMap.prototype.getOrInsert
    • WeakMap.prototype.getOrInsertComputed
• Don't call well-known Symbol methods for RegExp on primitive values following tc39/ecma262#3009:
  • For avoid performance regression, temporarily, only in own core-js implementations
  • Built-ins:
    • String.prototype.matchAll
    • String.prototype.match
    • String.prototype.replaceAll
    • String.prototype.replace
    • String.prototype.search
    • String.prototype.split
• Added workaround for the Uint8Array.prototype.setFromBase64 bug in some of Linux builds of WebKit
• Implemented early-error iterator closing following tc39/ecma262#3467, including fix of a WebKit bug, in the following methods:
  • Iterator.prototype.drop
  • Iterator.prototype.every
  • Iterator.prototype.filter
  • Iterator.prototype.find
  • Iterator.prototype.flatMap
  • Iterator.prototype.forEach
  • Iterator.prototype.map
  • Iterator.prototype.reduce
  • Iterator.prototype.some
  • Iterator.prototype.take
• Fixed missing forced replacement of AsyncIterator helpers
• Added closing of sync iterator when async wrapper yields a rejection following tc39/ecma262#2600. Affected methods:
  • Array.fromAsync (due to the lack of async feature detection capability - temporarily, only in own core-js implementation)
  • AsyncIterator.from
  • Iterator.prototype.toAsync
• Added detection for throwing on undefined initial parameter in Iterator.prototype.reduce (see WebKit bug)
• core-js-compat and core-js-builder API:
  • Added 'intersect' support for targets.esmodules (Babel 7 behavior)
  • Fixed handling of targets.esmodules: true (Babel 7 behavior)
• Compat data improvements:
  • Explicit Resource Management features disabled (again) in V8 ~ Chromium 135 and re-added in 136
  • RegExp.escape marked as shipped from V8 ~ Chromium 136
  • Error.isError marked as shipped from FF138
  • Explicit Resource Management features re-enabled in Deno 2.2.10
  • Iterator helpers proposal features marked as supported from Deno 1.38.1 since it seems they were disabled in 1.38.0
  • Iterator.prototype.{ drop, reduce, take } methods marked as fixed in Bun 1.2.11
  • Added NodeJS 24.0 compat data mapping
  • Updated Electron 36 and added Electron 37 compat data mapping
  • Added Opera Android 88 and 89 compat data mapping
  • Added Oculus Quest Browser 37 compat data mapping

• Changes v3.40.0...v3.41.0 (85 commits)
• RegExp.escape proposal:
  • Built-ins:
    • RegExp.escape
  • Moved to stable ES, February 2025 TC39 meeting
  • Added es. namespace module, /es/ and /stable/ namespaces entries
• Float16 proposal:
  • Built-ins:
    • Math.f16round
    • DataView.prototype.getFloat16
    • DataView.prototype.setFloat16
  • Moved to stable ES, February 2025 TC39 meeting
  • Added es. namespace modules, /es/ and /stable/ namespaces entries
• Math.clamp stage 1 proposal:
  • Built-ins:
    • Math.clamp
  • Extracted from old Math extensions proposal, February 2025 TC39 meeting
  • Added arguments validation
  • Added new entries
• Added a workaround of a V8 AsyncDisposableStack bug, tc39/proposal-explicit-resource-management/256
• Compat data improvements:
  • DisposableStack, SuppressedError and Iterator.prototype[@@dispose] marked as shipped from V8 ~ Chromium 134
  • Error.isError added and marked as shipped from V8 ~ Chromium 134
  • Math.f16round and DataView.prototype.{ getFloat16, setFloat16 } marked as shipped from V8 ~ Chromium 135
  • Iterator helpers proposal features marked as shipped from Safari 18.4
  • JSON.parse source text access proposal features marked as shipped from Safari 18.4
  • Math.sumPrecise marked as shipped from FF137
  • Added Deno 2.2 compat data and compat data mapping
    • Explicit Resource Management features are available in V8 ~ Chromium 134, but not in Deno 2.2 based on it
  • Updated Electron 35 and added Electron 36 compat data mapping
  • Updated Opera Android 87 compat data mapping
  • Added Samsung Internet 28 compat data mapping
  • Added Oculus Quest Browser 36 compat data mapping

• Changes v3.39.0...v3.40.0 (130 commits)
• Added Error.isError stage 3 proposal:
  • Added built-ins:
    • Error.isError
  • We have no bulletproof way to polyfill this method / check if the object is an error, so it's an enough naive implementation that is marked as .sham
• Explicit Resource Management stage 3 proposal:
  • Updated the way async disposing of only sync disposable resources, tc39/proposal-explicit-resource-management/218
• Iterator sequencing stage 2.7 proposal:
  • Reuse IteratorResult objects when possible, tc39/proposal-iterator-sequencing/17, tc39/proposal-iterator-sequencing/18, December 2024 TC39 meeting
• Added a fix of V8 < 12.8 / NodeJS < 22.10 bug with handling infinite length of set-like objects in Set methods
• Optimized DataView.prototype.{ getFloat16, setFloat16 } performance, #1379, thanks @LeviPesin
• Dropped unneeded feature detection of non-standard %TypedArray%.prototype.toSpliced
• Dropped possible re-usage of some non-standard / early stage features (like Math.scale) available on global
• Some other minor improvements
• Compat data improvements:
  • RegExp.escape marked as shipped from Safari 18.2
  • Promise.try marked as shipped from Safari 18.2
  • Math.f16round and DataView.prototype.{ getFloat16, setFloat16 } marked as shipped from Safari 18.2
  • Uint8Array to / from base64 and hex proposal methods marked as shipped from Safari 18.2
  • JSON.parse source text access proposal features marked as shipped from FF135
  • RegExp.escape marked as shipped from FF134
  • Promise.try marked as shipped from FF134
  • Symbol.dispose, Symbol.asyncDispose and Iterator.prototype[@@dispose] marked as shipped from FF135
  • JSON.parse source text access proposal features marked as shipped from Bun 1.1.43
  • Fixed NodeJS version where URL.parse was added - 22.1 instead of 22.0
  • Added Deno 2.1 compat data mapping
  • Added Rhino 1.8.0 compat data with significant number of modern features
  • Added Electron 35 compat data mapping
  • Updated Opera 115+ compat data mapping
  • Added Opera Android 86 and 87 compat data mapping

• Changes v3.38.1...v3.39.0
• Iterator helpers proposal:
  • Built-ins:
    • Iterator
      • Iterator.from
      • Iterator.prototype.drop
      • Iterator.prototype.every
      • Iterator.prototype.filter
      • Iterator.prototype.find
      • Iterator.prototype.flatMap
      • Iterator.prototype.forEach
      • Iterator.prototype.map
      • Iterator.prototype.reduce
      • Iterator.prototype.some
      • Iterator.prototype.take
      • Iterator.prototype.toArray
      • Iterator.prototype[@@toStringTag]
  • Moved to stable ES, October 2024 TC39 meeting
  • Added es. namespace modules, /es/ and /stable/ namespaces entries
• Promise.try:
  • Built-ins:
    • Promise.try
  • Moved to stable ES, October 2024 TC39 meeting
  • Added es. namespace module, /es/ and /stable/ namespaces entries
  • Fixed /actual|full/promise/try entries for the callback arguments support
• Math.sumPrecise proposal:
  • Built-ins:
    • Math.sumPrecise
  • Moved to stage 3, October 2024 TC39 meeting
  • Added /actual/ namespace entries, unconditional forced replacement changed to feature detection
• Added Iterator sequencing stage 2.7 proposal:
  • Added built-ins:
    • Iterator.concat
• Map upsert stage 2 proposal:
  • Updated to the new API following the October 2024 TC39 meeting
  • Added built-ins:
    • Map.prototype.getOrInsert
    • Map.prototype.getOrInsertComputed
    • WeakMap.prototype.getOrInsert
    • WeakMap.prototype.getOrInsertComputed
• Extractors proposal moved to stage 2, October 2024 TC39 meeting
• Usage of @@species pattern removed from %TypedArray% and ArrayBuffer methods, tc39/ecma262/3450:
  • Built-ins:
    • %TypedArray%.prototype.filter
    • %TypedArray%.prototype.filterReject
    • %TypedArray%.prototype.map
    • %TypedArray%.prototype.slice
    • %TypedArray%.prototype.subarray
    • ArrayBuffer.prototype.slice
• Some other minor improvements
• Compat data improvements:
  • Uint8Array to / from base64 and hex proposal methods marked as shipped from FF133
  • Added NodeJS 23.0 compat data mapping
  • self descriptor is fixed in Deno 1.46.0
  • Added Deno 1.46 and 2.0 compat data mapping
  • Iterator helpers proposal methods marked as shipped from Bun 1.1.31
  • Added Electron 34 and updated Electron 33 compat data mapping
  • Added Opera Android 85 compat data mapping
  • Added Oculus Quest Browser 35 compat data mapping