• Added a fix for a NodeJS 19.9.0 URL.canParse bug
• Compat data improvements:
  • JSON.parse source text access proposal features marked as supported from V8 ~ Chrome 114
  • ArrayBuffer.prototype.transfer and friends proposal features marked as supported from V8 ~ Chrome 114
  • URLSearchParams.prototype.size marked as supported from V8 ~ Chrome 113

• Added URL.canParse method, url/763
• Set methods proposal:
  • Removed sort from Set.prototype.intersection, March 2023 TC39 meeting, proposal-set-methods/94
• Iterator Helpers proposals (sync, async):
  • Validate arguments before opening iterator, March 2023 TC39 meeting, proposal-iterator-helpers/265
• Explicit Resource Management proposals (sync, async):
  • (Async)DisposableStack.prototype.move marks the original stack as disposed, #1226
  • Some simplifications like proposal-explicit-resource-management/150
• Iterator.range proposal:
  • Moved to Stage 2, March 2023 TC39 meeting
• Decorator Metadata proposal:
  • Returned to usage Symbol.metadata, March 2023 TC39 meeting, proposal-decorator-metadata/12
• Compat data improvements:
  • URLSearchParams.prototype.size marked as supported from FF112, NodeJS 19.8 and Deno 1.32
  • Added Safari 16.4 compat data
  • Added Deno 1.32 compat data mapping
  • Added Electron 25 and updated 24 compat data mapping
  • Added Samsung Internet 21 compat data mapping
  • Added Quest Browser 26 compat data mapping
  • Updated Opera Android 74 compat data

• Fixed dependencies of some entries
• Fixed ToString conversion / built-ins nature of some accessors
• String.prototype.{ isWellFormed, toWellFormed } marked as supported from V8 ~ Chrome 111
• Added Opera Android 74 compat data mapping

• Added URLSearchParams.prototype.size getter, url/734
• Allowed cloning resizable ArrayBuffers in the structuredClone polyfill
• Fixed wrong export in /(stable|actual|full)/instance/unshift entries, #1207
• Compat data improvements:
  • Set methods proposal marked as supported from Bun 0.5.7
  • String.prototype.toWellFormed marked as fixed from Bun 0.5.7
  • Added Deno 1.31 compat data mapping

I highly recommend reading this: So, what's next?

• Change Array by copy proposal:
  • Methods:
    • Array.prototype.toReversed
    • Array.prototype.toSorted
    • Array.prototype.toSpliced
    • Array.prototype.with
    • %TypedArray%.prototype.toReversed
    • %TypedArray%.prototype.toSorted
    • %TypedArray%.prototype.with
  • Moved to stable ES, January 2023 TC39 meeting
  • Added es. namespace modules, /es/ and /stable/ namespaces entries
• Added JSON.parse source text access Stage 3 proposal
  • Methods:
    • JSON.parse patched for support source in reviver function arguments
    • JSON.rawJSON
    • JSON.isRawJSON
    • JSON.stringify patched for support JSON.rawJSON
• Added ArrayBuffer.prototype.transfer and friends Stage 3 proposal:
  • Built-ins:
    • ArrayBuffer.prototype.detached
    • ArrayBuffer.prototype.transfer (only in runtimes with native structuredClone with ArrayBuffer transfer support)
    • ArrayBuffer.prototype.transferToFixedLength (only in runtimes with native structuredClone with ArrayBuffer transfer support)
  • In backwards, in runtimes with native ArrayBuffer.prototype.transfer, but without proper structuredClone, added ArrayBuffer transfer support to structuredClone polyfill
• Iterator Helpers proposal:
  • Splitted into 2 (sync and async) proposals, async version moved back to Stage 2, January 2023 TC39 meeting
  • Allowed interleaved mapping in AsyncIterator helpers, proposal-iterator-helpers/262
• Explicit Resource Management Stage 3 and Async Explicit Resource Management Stage 2 proposals:
  • InstallErrorCause removed from SuppressedError, January 2023 TC39 meeting, proposal-explicit-resource-management/145
  • Simplified internal behaviour of { AsyncDisposableStack, DisposableStack }.prototype.use, proposal-explicit-resource-management/143
• Added Symbol predicates Stage 2 proposal
  • Methods:
    • Symbol.isRegistered
    • Symbol.isWellKnown
• Number.range Stage 1 proposal and method renamed to Iterator.range
• Function.prototype.unThis Stage 0 proposal and method renamed to Function.prototype.demethodize
• Fixed Safari String.prototype.toWellFormed ToString conversion bug
• Improved some cases handling of array-replacer in JSON.stringify symbols handling fix
• Fixed many other old JSON.{ parse, stringify } bugs (numbers instead of strings as keys in replacer, handling negative zeroes, spaces, some more handling symbols cases, etc.)
• Fixed configurability and ToString conversion of some accessors
• Added throwing proper errors on an incorrect context in some ArrayBuffer and DataView methods
• Some minor DataView and %TypedArray% polyfills optimizations
• Added proper error on the excess number of trailing = in the atob polyfill
• Fixed theoretically possible ReDoS vulnerabilities in String.prototype.{ trim, trimEnd, trimRight }, parse(Int|Float), Number, atob, and URL polyfills in some ancient engines
• Compat data improvements:
  • RegExp.prototype.flags marked as fixed from V8 ~ Chrome 111
  • Added Opera Android 73 compat data mapping
• Added TypeScript definitions to core-js-builder

• Set methods proposal updates:
  • Closing of iterators of Set-like objects on early exit, proposal-set-methods/85
  • Some other minor internal changes
• Added one more workaround of a webpack dev server bug on IE global methods, #1161
• Fixed possible String.{ raw, cooked } error with empty template array
• Used non-standard V8 Error.captureStackTrace instead of stack parsing in new error classes / wrappers where it's possible
• Added detection correctness of iteration to Promise.{ allSettled, any } feature detection, Hermes issue
• Compat data improvements:
  • Change Array by copy proposal marked as supported from V8 ~ Chrome 110
  • Added Samsung Internet 20 compat data mapping
  • Added Quest Browser 25 compat data mapping
  • Added React Native 0.71 Hermes compat data
  • Added Electron 23 and 24 compat data mapping
  • self marked as fixed in Deno 1.29.3, deno/17362
• Minor tweaks of minification settings for core-js-bundle
• Refactoring, some minor fixes, improvements, optimizations

• Fixed a Chakra-based MS Edge (18-) bug that unfreeze (O_o) frozen arrays used as WeakMap keys
• Fixing of the previous bug also fixes some cases of String.dedent in MS Edge
• Fixed dependencies of some entries

• 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.toAsync
      • Iterator.prototype[@@toStringTag]
    • AsyncIterator
      • AsyncIterator.from
      • AsyncIterator.prototype.drop
      • AsyncIterator.prototype.every
      • AsyncIterator.prototype.filter
      • AsyncIterator.prototype.find
      • AsyncIterator.prototype.flatMap
      • AsyncIterator.prototype.forEach
      • AsyncIterator.prototype.map
      • AsyncIterator.prototype.reduce
      • AsyncIterator.prototype.some
      • AsyncIterator.prototype.take
      • AsyncIterator.prototype.toArray
      • AsyncIterator.prototype[@@toStringTag]
  • Moved to Stage 3, November 2022 TC39 meeting
  • Added /actual/ entries, unconditional forced replacement disabled for features that survived to Stage 3
  • .from accept strings, .flatMap throws on strings returned from the callback, proposal-iterator-helpers/244, proposal-iterator-helpers/250
  • .from and .flatMap throws on non-object iterators, proposal-iterator-helpers/253
• Set methods proposal:
  • Built-ins:
    • Set.prototype.intersection
    • Set.prototype.union
    • Set.prototype.difference
    • Set.prototype.symmetricDifference
    • Set.prototype.isSubsetOf
    • Set.prototype.isSupersetOf
    • Set.prototype.isDisjointFrom
  • Moved to Stage 3, November 2022 TC39 meeting
  • Reimplemented with new semantics:
    • Optimized performance (iteration over lowest set)
    • Accepted only Set-like objects as an argument, not all iterables
    • Accepted only Sets as this, no @@species support, and other minor changes
  • Added /actual/ entries, unconditional forced replacement changed to feature detection
  • For avoiding breaking changes:
    • New versions of methods are implemented as new modules and available in new entries or entries where old versions of methods were not available before (like /actual/ namespace)
    • In entries where they were available before (like /full/ namespace), those methods are available with fallbacks to old semantics (in addition to Set-like, they accept iterable objects). This behavior will be removed from the next major release
• Well-Formed Unicode Strings proposal:
  • Methods:
    • String.prototype.isWellFormed
    • String.prototype.toWellFormed
  • Moved to Stage 3, November 2022 TC39 meeting
  • Added /actual/ entries, disabled unconditional forced replacement
• Explicit resource management Stage 3 and Async explicit resource management Stage 2 proposals:
  • Renamed from "using statement" and splitted into 2 (sync and async) proposals
  • In addition to already present well-known symbols, added new 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]
  • Sync version of this proposal moved to Stage 3, November 2022 TC39 meeting
  • Added /actual/ namespace entries for Stage 3 proposal
• Added String.dedent stage 2 proposal
  • Method String.dedent
  • Throws an error on non-frozen raw templates for avoiding possible breaking changes in the future, proposal-string-dedent/75
• Compat data targets improvements:
  • React Native from 0.70 shipped with Hermes as the default engine. However, bundled Hermes versions differ from standalone Hermes releases. So added react-native target for React Native with bundled Hermes.
  • According to the documentation, Oculus Browser was renamed to Meta Quest Browser, so oculus target was renamed to quest.
  • opera_mobile target name is confusing since it contains data for the Chromium-based Android version, but iOS Opera is Safari-based. So opera_mobile target was renamed to opera-android.
  • android target name is also confusing for someone - that means Android WebView, some think thinks that it's Chrome for Android, but they have some differences. For avoiding confusion, added chrome-android target.
  • For consistency with two previous cases, added firefox-android target.
  • For avoiding breaking changes, the oculus and opera_mobile fields are available in the compat data till the next major release.
• Compat data improvements:
  • Array.fromAsync marked as supported from Bun 0.3.0
  • String.prototype.{ isWellFormed, toWellFormed } marked as supported from Bun 0.4.0
  • Change Array by copy proposal marked as supported from Deno 1.27, deno/16429
  • Added Deno 1.28 / 1.29 compat data mapping
  • Added NodeJS 19.2 compat data mapping
  • Added Samsung Internet 19.0 compat data mapping
  • Added Quest Browser 24.0 compat data mapping
  • Fixed the first version in the Chromium-based Edge compat data mapping
• { Map, WeakMap }.prototype.emplace became stricter by the spec draft
• Smoothed behavior of some conflicting proposals
• Removed some generic behavior (like @@species pattern) of some .prototype methods from the new collections methods proposal and the Array deduplication proposal that most likely will not be implemented since it contradicts the current TC39 policy
• Added pure version of the Number constructor, #1154, #1155, thanks @trosos
• Added set(Timeout|Interval|Immediate) extra arguments fix for Bun 0.3.0- (similarly to IE9-), bun/1633
• Fixed handling of sparse arrays in structuredClone, #1156
• Fixed a theoretically possible future conflict of polyfills definitions in the pure version
• Some refactoring and optimization

• Disabled forced replacing of Array.fromAsync since it's on Stage 3
• Avoiding a check of the target in the internal function-uncurry-this helper where it's not required - minor optimization and preventing problems in some broken environments, a workaround of #1141
• V8 will not ship Array.prototype.{ group, groupToMap } in V8 ~ Chromium 108, proposal-array-grouping/44

• Array.fromAsync proposal:
  • Moved to Stage 3, September TC39 meeting
  • Avoid observable side effects of %Array.prototype.values% usage in array-like branch, proposal-array-from-async/30
• Added well-formed unicode strings stage 2 proposal:
  • String.prototype.isWellFormed
  • String.prototype.toWellFormed
• Recent updates of the iterator helpers proposal:
  • Added a counter parameter to helpers, proposal-iterator-helpers/211
  • Don't await non-objects returned from functions passed to AsyncIterator helpers, proposal-iterator-helpers/239
  • { Iterator, AsyncIterator }.prototype.flatMap supports returning both - iterables and iterators, proposal-iterator-helpers/233
  • Early exit on broken .next in missed cases of { Iterator, AsyncIterator }.from, proposal-iterator-helpers/232
• Added self polyfill as a part of The Minimum Common Web Platform API, specification, #1118
• Added inverse option to core-js-compat, #1119
• Added format option to core-js-builder, #1120
• Added NodeJS 19.0 compat data
• Added Deno 1.26 and 1.27 compat data
• Added Opera Android 72 compat data mapping
• Updated Electron 22 compat data mapping