Changes from October 2021 TC39 meeting

CHANGELOG.md

@@ -1,5 +1,9 @@
 ## Changelog
 ##### Unreleased
+- [`Array` grouping proposal](https://github.com/tc39/proposal-array-grouping):
+  - Moved to the stage 2
+  - Added `Array.prototype.groupByMap` 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`

README.md

@@ -101,6 +101,7 @@ Promise.resolve(32).then(x => console.log(x)); // => 32
       - [`Iterator` helpers](#iterator-helpers)
       - [New `Set` methods](#new-set-methods)
       - [`Map.prototype.emplace`](#mapprototypeemplace)
+      - [`Array` grouping](#array-grouping)
       - [Change `Array` by copy](#change-array-by-copy)
       - [`Array.isTemplateObject`](#arrayistemplateobject)
       - [`Symbol.{ asyncDispose, dispose }` for `using` statement](#symbol-asyncdispose-dispose--for-using-statement)
@@ -112,7 +113,6 @@ Promise.resolve(32).then(x => console.log(x)); // => 32
       - [`compositeKey` and `compositeSymbol`](#compositekey-and-compositesymbol)
       - [`Array.fromAsync`](#arrayfromasync)
       - [`Array` filtering](#array-filtering)
-      - [`Array` grouping](#array-grouping)
       - [`Array` deduplication](#array-deduplication)
       - [Getting last item from `Array`](#getting-last-item-from-array)
       - [`Number.range`](#numberrange)
@@ -2353,21 +2353,16 @@ console.log(compositeSymbol(1, a, 2, b) === compositeSymbol(1, a, 2, b)); // =>
 console.log(compositeSymbol(a, a) === compositeSymbol(a, a)); // => true
 ```
 ##### [`Array.fromAsync`](https://github.com/tc39/proposal-array-from-async)[⬆](#index)
-Modules [`esnext.array.from-async`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array.from-async.js) and [`esnext.typed-array.from-async`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.typed-array.from-async.js)
+Modules [`esnext.array.from-async`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array.from-async.js).
 ```js
 class Array {
   static fromAsync(asyncItems: AsyncIterable | Iterable | ArrayLike, mapfn?: (value: any, index: number) => any, thisArg?: any): Array;
 }
-
-class %TypedArray% {
-  static fromAsync(asyncItems: AsyncIterable | Iterable | ArrayLike, mapfn?: (value: number, index: number, target) => number, thisArg?: any): %TypedArray%;
-}
 ```
 [*CommonJS entry points:*](#commonjs-api)
 ```js
 core-js/proposals/array-from-async
 core-js(-pure)/features/array/from-async
-core-js/features/typed-array/from-async
 ```
 [*Example*](https://goo.gl/Jt7SsD):
 ```js
@@ -2395,26 +2390,25 @@ core-js/features/typed-array/filter-reject
 [1, 2, 3, 4, 5].filterReject(it => it % 2); // => [2, 4]
 ````
 ##### [`Array` grouping](#https://github.com/tc39/proposal-array-grouping)[⬆](#index)
-Modules [`esnext.array.group-by`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array.group-by.js) and [`esnext.typed-array.group-by`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.typed-array.group-by.js).
+Modules [`esnext.array.group-by`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array.group-by.js), [`esnext.array.group-by-map`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array.group-by-map.js).
 ```js
 class Array {
   groupBy(callbackfn: (value: any, index: number, target: any) => key, thisArg?: any): { [key]: Array<mixed> };
   groupByMap(callbackfn: (value: any, index: number, target: any) => key, thisArg?: any): Map<key, Array<mixed>>;
 }
-
-class %TypedArray% {
-  groupBy(callbackfn: (value: number, index: number, target: %TypedArray%) => key, thisArg?: any): { [key]: %TypedArray% };
-}
 ```
 [*CommonJS entry points:*](#commonjs-api)
 ```
 core-js/proposals/array-grouping
 core-js(-pure)/features/array(/virtual)/group-by
-core-js/features/typed-array/group-by
+core-js(-pure)/features/array(/virtual)/group-by-map
 ```
-[*Examples*](t.ly/VggI):
+[*Examples*](t.ly/xEqc):
 ```js
 [1, 2, 3, 4, 5].groupBy(it => it % 2); // => { 1: [1, 3, 5], 0: [2, 4] }
+const map = [1, 2, 3, 4, 5].groupByMap(it => it % 2);
+map.get(1); // => [1, 3, 5]
+map.get(0); // => [2, 4]
 ````
 ##### [Array deduplication](https://github.com/tc39/proposal-array-unique)[⬆](#index)
 Modules [`esnext.array.unique-by`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.array.unique-by.js) and [`esnext.typed-array.unique-by`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.typed-array.unique-by.js)
@@ -3086,4 +3080,4 @@ console.log(getIteratorMethod({})); // undefined
 - ES `Proxy` can't be polyfilled, you can try to use [`proxy-polyfill`](https://github.com/GoogleChrome/proxy-polyfill) which provides a very little subset of features.
 - ES `String#normalize` is not a very useful feature, but this polyfill will be very large. If you need it, you can use [unorm](https://github.com/walling/unorm/).
 - ECMA-402 `Intl` is missed because of the size. You can use [those polyfills](https://formatjs.io/docs/polyfills).
-- `window.fetch` is not a cross-platform feature, in some environments, it makes no sense. For this reason, I don't think it should be in `core-js`. Looking at a large number of requests it *might be*  added in the future. Now you can use, for example, [this polyfill](https://github.com/github/fetch).
+- `window.fetch` is not a cross-platform feature, in some environments, it makes no sense. For this reason, I don't think it should be in `core-js`. Looking at a large number of requests it *might be*  added in the future. Now you can use, for example, [this polyfill](https://github.com/github/fetch).

packages/core-js-compat/src/data.mjs

@@ -1451,6 +1451,8 @@ export const data = {
   },
   'esnext.array.group-by': {
   },
+  'esnext.array.group-by-map': {
+  },
   'esnext.array.is-template-object': {
   },
   // TODO: Remove from `core-js@4`
@@ -1728,6 +1730,7 @@ export const data = {
   // TODO: Remove from `core-js@4`
   'esnext.symbol.replace-all': {
   },
+  // TODO: Remove from `core-js@4`
   'esnext.typed-array.from-async': {
   },
   // TODO: Remove from `core-js@4`
@@ -1745,6 +1748,7 @@ export const data = {
     chrome: '97',
     safari: '15.4',
   },
+  // TODO: Remove from `core-js@4`
   'esnext.typed-array.group-by': {
   },
   'esnext.typed-array.to-reversed': {

packages/core-js-compat/src/modules-by-versions.mjs

@@ -112,6 +112,7 @@ export default {
     'esnext.typed-array.from-async',
   ],
   '3.20': [
+    'esnext.array.group-by-map',
     'esnext.array.to-reversed',
     'esnext.array.to-sorted',
     'esnext.array.to-spliced',

packages/core-js/features/array/group-by-map.js

@@ -0,0 +1,5 @@
+require('../../modules/es.map');
+require('../../modules/esnext.array.group-by-map');
+var entryUnbind = require('../../internals/entry-unbind');
+
+module.exports = entryUnbind('Array', 'groupByMap');

packages/core-js/features/array/index.js

@@ -10,6 +10,7 @@ require('../../modules/esnext.array.filter-reject');
 require('../../modules/esnext.array.find-last');
 require('../../modules/esnext.array.find-last-index');
 require('../../modules/esnext.array.group-by');
+require('../../modules/esnext.array.group-by-map');
 require('../../modules/esnext.array.is-template-object');
 require('../../modules/esnext.array.last-item');
 require('../../modules/esnext.array.last-index');

packages/core-js/features/array/virtual/group-by-map.js

@@ -0,0 +1,5 @@
+require('../../../modules/es.map');
+require('../../../modules/esnext.array.group-by-map');
+var entryVirtual = require('../../../internals/entry-virtual');
+
+module.exports = entryVirtual('Array').groupByMap;

packages/core-js/features/array/virtual/index.js

@@ -8,6 +8,7 @@ require('../../../modules/esnext.array.filter-reject');
 require('../../../modules/esnext.array.find-last');
 require('../../../modules/esnext.array.find-last-index');
 require('../../../modules/esnext.array.group-by');
+require('../../../modules/esnext.array.group-by-map');
 require('../../../modules/esnext.array.to-reversed');
 require('../../../modules/esnext.array.to-sorted');
 require('../../../modules/esnext.array.to-spliced');

packages/core-js/internals/array-group-by.js

@@ -27,6 +27,7 @@ module.exports = function ($this, callbackfn, that, specificConstructor) {
     if (key in target) push(target[key], value);
     else target[key] = [value];
   }
+  // TODO: Remove this block from `core-js@4`
   if (specificConstructor) {
     Constructor = specificConstructor(O);
     if (Constructor !== Array) {

packages/core-js/modules/esnext.array.group-by-map.js

@@ -0,0 +1,38 @@
+'use strict';
+var $ = require('../internals/export');
+var getBuiltIn = require('../internals/get-built-in');
+var bind = require('../internals/function-bind-context');
+var uncurryThis = require('../internals/function-uncurry-this');
+var IndexedObject = require('../internals/indexed-object');
+var toObject = require('../internals/to-object');
+var lengthOfArrayLike = require('../internals/length-of-array-like');
+var addToUnscopables = require('../internals/add-to-unscopables');
+
+var Map = getBuiltIn('Map');
+var MapPrototype = Map.prototype;
+var mapGet = uncurryThis(MapPrototype.get);
+var mapHas = uncurryThis(MapPrototype.has);
+var mapSet = uncurryThis(MapPrototype.set);
+var push = uncurryThis([].push);
+
+// `Array.prototype.groupByMap` method
+// https://github.com/tc39/proposal-array-grouping
+$({ target: 'Array', proto: true }, {
+  groupByMap: function groupByMap(callbackfn /* , thisArg */) {
+    var O = toObject(this);
+    var self = IndexedObject(O);
+    var boundFunction = bind(callbackfn, arguments.length > 1 ? arguments[1] : undefined);
+    var map = new Map();
+    var length = lengthOfArrayLike(self);
+    var index = 0;
+    var key, value;
+    for (;length > index; index++) {
+      value = self[index];
+      key = boundFunction(value, index, O);
+      if (mapHas(map, key)) push(mapGet(map, key), value);
+      else mapSet(map, key, [value]);
+    } return map;
+  }
+});
+
+addToUnscopables('groupByMap');

packages/core-js/modules/esnext.array.group-by.js

@@ -1,15 +1,14 @@
 'use strict';
 var $ = require('../internals/export');
 var $groupBy = require('../internals/array-group-by');
-var arraySpeciesConstructor = require('../internals/array-species-constructor');
 var addToUnscopables = require('../internals/add-to-unscopables');
 
 // `Array.prototype.groupBy` method
 // https://github.com/tc39/proposal-array-grouping
 $({ target: 'Array', proto: true }, {
   groupBy: function groupBy(callbackfn /* , thisArg */) {
     var thisArg = arguments.length > 1 ? arguments[1] : undefined;
-    return $groupBy(this, callbackfn, thisArg, arraySpeciesConstructor);
+    return $groupBy(this, callbackfn, thisArg);
   }
 });
 

packages/core-js/modules/esnext.typed-array.from-async.js

@@ -1,4 +1,5 @@
 'use strict';
+// TODO: Remove from `core-js@4`
 var getBuiltIn = require('../internals/get-built-in');
 var aConstructor = require('../internals/a-constructor');
 var arrayFromAsync = require('../internals/array-from-async');

packages/core-js/modules/esnext.typed-array.group-by.js

@@ -1,4 +1,5 @@
 'use strict';
+// TODO: Remove from `core-js@4`
 var ArrayBufferViewCore = require('../internals/array-buffer-view-core');
 var $groupBy = require('../internals/array-group-by');
 var typedArraySpeciesConstructor = require('../internals/typed-array-species-constructor');

packages/core-js/proposals/array-from-async.js

@@ -1,3 +1,4 @@
 // https://github.com/tc39/proposal-array-from-async
 require('../modules/esnext.array.from-async');
+// TODO: Remove from `core-js@4`
 require('../modules/esnext.typed-array.from-async');

packages/core-js/proposals/array-grouping.js

@@ -1,3 +1,5 @@
 // https://github.com/tc39/proposal-array-grouping
 require('../modules/esnext.array.group-by');
+require('../modules/esnext.array.group-by-map');
+// TODO: Remove from `core-js@4`
 require('../modules/esnext.typed-array.group-by');

packages/core-js/stage/1.js

@@ -1,6 +1,5 @@
 require('../proposals/array-filtering');
 require('../proposals/array-from-async');
-require('../proposals/array-grouping');
 require('../proposals/array-last');
 require('../proposals/array-unique');
 require('../proposals/collection-methods');

packages/core-js/stage/2.js

@@ -1,3 +1,4 @@
+require('../proposals/array-grouping');
 require('../proposals/array-is-template-object');
 require('../proposals/change-array-by-copy');
 require('../proposals/decorators');

scripts/check-compat-tests.mjs

@@ -30,7 +30,9 @@ const ignore = new Set([
   'esnext.string.at',
   'esnext.symbol.pattern-match',
   'esnext.symbol.replace-all',
+  'esnext.typed-array.from-async',
   'esnext.typed-array.filter-out',
+  'esnext.typed-array.group-by',
   'esnext.weak-map.upsert',
 ]);
 

tests/commonjs.mjs

@@ -567,6 +567,7 @@ for (PATH of ['core-js-pure', 'core-js']) {
     ok(load(NS, 'array/find-last')([1, 2, 3], it => it % 2) === 3);
     ok(load(NS, 'array/find-last-index')([1, 2, 3], it => it % 2) === 2);
     ok(typeof load(NS, 'array/group-by') == 'function');
+    ok(typeof load(NS, 'array/group-by-map') == 'function');
     ok(typeof load(NS, 'array/is-template-object') == 'function');
     load(NS, 'array/last-item');
     load(NS, 'array/last-index');
@@ -580,6 +581,7 @@ for (PATH of ['core-js-pure', 'core-js']) {
     ok(load(NS, 'array/virtual/find-last').call([1, 2, 3], it => it % 2) === 3);
     ok(load(NS, 'array/virtual/find-last-index').call([1, 2, 3], it => it % 2) === 2);
     ok(typeof load(NS, 'array/virtual/group-by') == 'function');
+    ok(typeof load(NS, 'array/virtual/group-by-map') == 'function');
     ok(typeof load(NS, 'array/virtual/unique-by') == 'function');
     ok(load(NS, 'array/virtual/with').call([1, 2, 3], 1, 4));
     ok(load(NS, 'array/virtual/to-reversed').call([1, 2, 3])[0] === 3);

tests/compat/tests.js

@@ -1514,9 +1514,6 @@ GLOBAL.tests = {
   'esnext.symbol.observable': function () {
     return Symbol.observable;
   },
-  'esnext.typed-array.from-async': function () {
-    return Int8Array.fromAsync;
-  },
   'esnext.typed-array.filter-reject': function () {
     return Int8Array.prototype.filterReject;
   },
@@ -1526,9 +1523,6 @@ GLOBAL.tests = {
   'esnext.typed-array.find-last-index': function () {
     return Int8Array.prototype.findLastIndex;
   },
-  'esnext.typed-array.group-by': function () {
-    return Int8Array.prototype.groupBy;
-  },
   'esnext.typed-array.to-reversed': function () {
     return Int8Array.prototype.toReversed;
   },

tests/pure/esnext.array.group-by-map.js

@@ -0,0 +1,37 @@
+import { STRICT } from '../helpers/constants';
+
+import Map from 'core-js-pure/es/map';
+import Symbol from 'core-js-pure/es/symbol';
+import from from 'core-js-pure/es/array/from';
+import groupByMap from 'core-js-pure/features/array/group-by-map';
+
+QUnit.test('Array#groupByMap', assert => {
+  assert.isFunction(groupByMap);
+  let array = [1];
+  const context = {};
+  groupByMap(array, function (value, key, that) {
+    assert.same(arguments.length, 3, 'correct number of callback arguments');
+    assert.same(value, 1, 'correct value in callback');
+    assert.same(key, 0, 'correct index in callback');
+    assert.same(that, array, 'correct link to array in callback');
+    assert.same(this, context, 'correct callback context');
+  }, context);
+  assert.true(groupByMap([], it => it) instanceof Map, 'returns Map');
+  assert.deepEqual(from(groupByMap([1, 2, 3], it => it % 2)), [[1, [1, 3]], [0, [2]]], '#1');
+  assert.deepEqual(
+    from(groupByMap([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12], it => `i${ it % 5 }`)),
+    [['i1', [1, 6, 11]], ['i2', [2, 7, 12]], ['i3', [3, 8]], ['i4', [4, 9]], ['i0', [5, 10]]],
+    '#2',
+  );
+  assert.deepEqual(from(groupByMap(Array(3), it => it)), [[undefined, [undefined, undefined, undefined]]], '#3');
+  if (STRICT) {
+    assert.throws(() => groupByMap(null, () => { /* empty */ }), TypeError);
+    assert.throws(() => groupByMap(undefined, () => { /* empty */ }), TypeError);
+  }
+  array = [1];
+  // eslint-disable-next-line object-shorthand -- constructor
+  array.constructor = { [Symbol.species]: function () {
+    return { foo: 1 };
+  } };
+  assert.same(groupByMap(array, Boolean).get(true).foo, undefined, 'no @@species');
+});

tests/pure/esnext.array.group-by.js

@@ -32,5 +32,5 @@ QUnit.test('Array#groupBy', assert => {
   array.constructor = { [Symbol.species]: function () {
     return { foo: 1 };
   } };
-  assert.same(groupBy(array, Boolean).true.foo, 1, '@@species');
+  assert.same(groupBy(array, Boolean).true.foo, undefined, 'no @@species');
 });

tests/tests/esnext.array.group-by-map.js

@@ -0,0 +1,39 @@
+import { STRICT } from '../helpers/constants';
+
+const { from } = Array;
+
+QUnit.test('Array#groupByMap', assert => {
+  const { groupByMap } = Array.prototype;
+  assert.isFunction(groupByMap);
+  assert.arity(groupByMap, 1);
+  assert.name(groupByMap, 'groupByMap');
+  assert.looksNative(groupByMap);
+  assert.nonEnumerable(Array.prototype, 'groupByMap');
+  let array = [1];
+  const context = {};
+  array.groupByMap(function (value, key, that) {
+    assert.same(arguments.length, 3, 'correct number of callback arguments');
+    assert.same(value, 1, 'correct value in callback');
+    assert.same(key, 0, 'correct index in callback');
+    assert.same(that, array, 'correct link to array in callback');
+    assert.same(this, context, 'correct callback context');
+  }, context);
+  assert.true([].groupByMap(it => it) instanceof Map, 'returns Map');
+  assert.deepEqual(from([1, 2, 3].groupByMap(it => it % 2)), [[1, [1, 3]], [0, [2]]], '#1');
+  assert.deepEqual(
+    from([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12].groupByMap(it => `i${ it % 5 }`)),
+    [['i1', [1, 6, 11]], ['i2', [2, 7, 12]], ['i3', [3, 8]], ['i4', [4, 9]], ['i0', [5, 10]]],
+    '#2',
+  );
+  assert.deepEqual(from(Array(3).groupByMap(it => it)), [[undefined, [undefined, undefined, undefined]]], '#3');
+  if (STRICT) {
+    assert.throws(() => groupByMap.call(null, () => { /* empty */ }), TypeError);
+    assert.throws(() => groupByMap.call(undefined, () => { /* empty */ }), TypeError);
+  }
+  array = [1];
+  // eslint-disable-next-line object-shorthand -- constructor
+  array.constructor = { [Symbol.species]: function () {
+    return { foo: 1 };
+  } };
+  assert.same(array.groupByMap(Boolean).get(true).foo, undefined, 'no @@species');
+});

tests/tests/esnext.array.group-by.js

@@ -35,5 +35,5 @@ QUnit.test('Array#groupBy', assert => {
   array.constructor = { [Symbol.species]: function () {
     return { foo: 1 };
   } };
-  assert.same(array.groupBy(Boolean).true.foo, 1, '@@species');
+  assert.same(array.groupBy(Boolean).true.foo, undefined, 'no @@species');
 });