.eslintrc.js

@@ -108,7 +108,7 @@ const base = {
   // disallow unnecessary labels
   'no-extra-label': ERROR,
   // disallow fallthrough of case statements
-  'no-fallthrough': ERROR,
+  'no-fallthrough': [ERROR, { commentPattern: 'break omitted' }],
   // disallow the use of leading or trailing decimal points in numeric literals
   'no-floating-decimal': ERROR,
   // disallow reassignments of native objects
@@ -1119,11 +1119,12 @@ module.exports = {
         'tests/compat/**',
       ],
       globals: {
-        compositeKey: READONLY,
-        compositeSymbol: READONLY,
         AsyncIterator: READONLY,
         Iterator: READONLY,
         Observable: READONLY,
+        compositeKey: READONLY,
+        compositeSymbol: READONLY,
+        structuredClone: READONLY,
       },
     },
     {

.github/workflows/ci.yml

@@ -30,6 +30,7 @@ jobs:
             package.json
             packages/*/package.json
       - run: npm i
+      - run: npx playwright install-deps
       - run: npm run ci-karma
 
   tests:

.gitignore

@@ -23,6 +23,7 @@ node_modules/
 /packages/core-js-compat/external.json
 /packages/core-js-compat/modules.json
 /packages/core-js-compat/modules-by-versions.json
+/packages/core-js-pure/actual/
 /packages/core-js-pure/es/
 /packages/core-js-pure/features/
 /packages/core-js-pure/internals/

CHANGELOG.md

@@ -2,6 +2,45 @@
 ##### Unreleased
 - Nothing
 
+##### 3.20.0 - 2021.12.16
+- Added `structuredClone` method [from the HTML spec](https://html.spec.whatwg.org/multipage/structured-data.html#dom-structuredclone), [see MDN](https://developer.mozilla.org/en-US/docs/Web/API/structuredClone)
+  - Includes all cases of cloning and transferring of required ECMAScript and platform types that can be polyfilled, for the details see [the caveats](https://github.com/zloirock/core-js#caveats-when-using-structuredclone-polyfill)
+  - Uses native structured cloning algorithm implementations where it's possible
+  - Includes the new semantic of errors cloning from [`html/5749`](https://github.com/whatwg/html/pull/5749)
+- Added `DOMException` polyfill, [the Web IDL spec](https://webidl.spec.whatwg.org/#idl-DOMException), [see MDN](https://developer.mozilla.org/en-US/docs/Web/API/DOMException)
+  - Includes `DOMException` and its attributes polyfills with fixes of many different engines bugs
+  - Includes `DOMException#stack` property polyfill in engines that should have it
+  - Reuses native `DOMException` implementations where it's possible (for example, in old NodeJS where it's not exposed as global)
+- Added [support of `cause` on all Error types](https://github.com/tc39/proposal-error-cause)
+- Added `Error.prototype.toString` method polyfill with fixes of many different bugs of JS engines
+- Added `Number.prototype.toExponential` method polyfill with fixes of many different bugs of JS engines
+- [`Array` grouping proposal](https://github.com/tc39/proposal-array-grouping):
+  - Moved to the stage 3
+  - Added `Array.prototype.groupByToMap` method
+  - Removed `@@species` support
+- Added [change `Array` by copy stage 2 proposal](https://github.com/tc39/proposal-change-array-by-copy):
+  - `Array.prototype.toReversed`
+  - `Array.prototype.toSorted`
+  - `Array.prototype.toSpliced`
+  - `Array.prototype.with`
+  - `%TypedArray%.prototype.toReversed`
+  - `%TypedArray%.prototype.toSorted`
+  - `%TypedArray%.prototype.toSpliced`
+  - `%TypedArray%.prototype.with`
+- Added `Iterator.prototype.toAsync` method from [the iterator helpers stage 2 proposal](https://github.com/tc39/proposal-iterator-helpers)
+- [`Array.fromAsync` proposal](https://github.com/tc39/proposal-array-from-async) moved to stage 2
+- Added [`String.cooked` stage 1 proposal](https://github.com/tc39/proposal-string-cooked):
+- Added [`Function.prototype.unThis` stage 0 proposal](https://github.com/js-choi/proposal-function-un-this)
+- Added [`Function.{ isCallable, isConstructor }` stage 0 proposal](https://github.com/caitp/TC39-Proposals/blob/trunk/tc39-reflect-isconstructor-iscallable.md):
+  - `Function.isCallable`
+  - `Function.isConstructor`
+- Added a workaround of most cases breakage modern `String#at` after loading obsolete `String#at` proposal module, [#1019](https://github.com/zloirock/core-js/issues/1019)
+- Fixed `Array.prototype.{ values, @@iterator }.name` in V8 ~ Chrome 45-
+- Fixed validation of typed arrays in typed arrays iteration methods in V8 ~ Chrome 50-
+- Extension of the API, [#1012](https://github.com/zloirock/core-js/issues/1012)
+  - Added a new `core-js/actual/**` namespace
+  - Added entry points for each finished post-ES6 proposal
+
 ##### 3.19.3 - 2021.12.06
 - Fixed internal slots check in methods of some built-in types, [#1017](https://github.com/zloirock/core-js/issues/1017)
 - Fixed `URLSearchParams` iterator `.next` that should be enumerable [by the spec](https://webidl.spec.whatwg.org/#es-iterator-prototype-object)