add Iterator sequencing stage 2.7 proposal

https://github.com/tc39/proposal-iterator-sequencing
zloirock · Oct 30, 2024 · 751bbae · 751bbae
1 parent dfc45d9
commit 751bbae
Show file tree

Hide file tree

Showing 12 changed files with 116 additions and 4 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -29,6 +29,9 @@
     - `Math.sumPrecise`
   - Moved to stage 3, [October 2024 TC39 meeting](https://github.com/tc39/proposal-math-sum/issues/19)
   - Added `/actual/` namespace entries, unconditional forced replacement changed to feature detection
+- Added [`Iterator` sequencing stage 2.7 proposal](https://github.com/tc39/proposal-iterator-sequencing):
+  - Added built-ins:
+    - `Iterator.concat`
 - [`Map` upsert stage 2 proposal](https://github.com/tc39/proposal-upsert):
   - [Updated to the new API following the October 2024 TC39 meeting](https://github.com/tc39/proposal-upsert/pull/58)
   - Added built-ins:

diff --git a/README.md b/README.md
@@ -168,6 +168,7 @@ structuredClone(new Set([1, 2, 3])); // => new Set([1, 2, 3])
       - [`Math.sumPrecise`](#mathsumprecise)
       - [`Symbol.metadata` for decorators metadata proposal](#symbolmetadata-for-decorators-metadata-proposal)
     - [Stage 2.7 proposals](#stage-27-proposals)
+      - [`Iterator` sequencing](#iterator-sequencing)
     - [Stage 2 proposals](#stage-2-proposals)
       - [`AsyncIterator` helpers](#asynciterator-helpers)
       - [`Iterator.range`](#iteratorrange)
@@ -2018,6 +2019,8 @@ globalThis.Array === Array; // => true
 ### ECMAScript proposals[⬆](#index)
 [The TC39 process.](https://tc39.github.io/process-document/)
 
+`core-js/stage/3` entry point contains only stage 3 proposals, `core-js/stage/2.7` - stage 2.7 and stage 3, etc.
+
 #### Finished proposals[⬆](#index)
 
 Finished (stage 4) proposals already marked in `core-js` as stable ECMAScript, they are available in `core-js/stable` and `core-js/es` namespace, you can find them in related sections of the README. However, even for finished proposals, `core-js` provides a way to include only features for a specific proposal like `core-js/proposals/proposal-name`.
@@ -2397,8 +2400,6 @@ core-js/proposals/set-methods-v2
 
 #### Stage 3 proposals[⬆](#index)
 
-`core-js/stage/3` entry point contains only stage 3 proposals, `core-js/stage/2.7` - stage 2.7 and stage 3, etc.
-
 [*CommonJS entry points:*](#commonjs-api)
 ```
 core-js(-pure)/stage/3
@@ -2647,7 +2648,25 @@ core-js(-pure)/actual|full/function/metadata
 core-js(-pure)/stage/2.7
 ```
 
-Nothing.
+##### [`Iterator` sequencing](https://github.com/tc39/proposal-iterator-sequencing)[⬆](#index)
+Module [`esnext.iterator.range`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.iterator.range.js)
+```ts
+class Iterator {
+  concat(...items: Array<IterableObject>): Iterator<any>;
+}
+```
+[*CommonJS entry points:*](#commonjs-api)
+```
+core-js/proposals/iterator-sequencing
+core-js(-pure)/full/iterator/concat
+```
+[*Example*](https://tinyurl.com/2522xjae):
+```js
+Iterator.concat(Iterator.from([0, 1]), [2, 3], function * () {
+  yield 4;
+  yield 5;
+}()).toArray(); // => [0, 1, 2, 3, 4, 5]
+```
 
 #### Stage 2 proposals[⬆](#index)
 [*CommonJS entry points:*](#commonjs-api)

diff --git a/packages/core-js-compat/src/data.mjs b/packages/core-js-compat/src/data.mjs
@@ -2249,6 +2249,8 @@ export const data = {
   // TODO: Remove from `core-js@4`
   'esnext.iterator.as-indexed-pairs': {
   },
+  'esnext.iterator.concat': {
+  },
   'esnext.iterator.dispose': {
   },
   // TODO: Remove from `core-js@4`

diff --git a/packages/core-js-compat/src/modules-by-versions.mjs b/packages/core-js-compat/src/modules-by-versions.mjs
@@ -268,6 +268,7 @@ export default {
     'es.iterator.take',
     'es.iterator.to-array',
     'es.promise.try',
+    'esnext.iterator.concat',
     'esnext.map.get-or-insert',
     'esnext.map.get-or-insert-computed',
     'esnext.weak-map.get-or-insert',

diff --git a/packages/core-js/full/iterator/concat.js b/packages/core-js/full/iterator/concat.js
@@ -0,0 +1,20 @@
+'use strict';
+require('../../modules/es.array.iterator');
+require('../../modules/es.object.to-string');
+require('../../modules/es.string.iterator');
+require('../../modules/es.iterator.constructor');
+require('../../modules/es.iterator.drop');
+require('../../modules/es.iterator.every');
+require('../../modules/es.iterator.filter');
+require('../../modules/es.iterator.find');
+require('../../modules/es.iterator.flat-map');
+require('../../modules/es.iterator.for-each');
+require('../../modules/es.iterator.map');
+require('../../modules/es.iterator.reduce');
+require('../../modules/es.iterator.some');
+require('../../modules/es.iterator.take');
+require('../../modules/es.iterator.to-array');
+require('../../modules/esnext.iterator.concat');
+var path = require('../../internals/path');
+
+module.exports = path.Iterator.concat;
diff --git a/packages/core-js/full/iterator/index.js b/packages/core-js/full/iterator/index.js
@@ -1,5 +1,6 @@
 'use strict';
 var parent = require('../../actual/iterator');
+require('../../modules/esnext.iterator.concat');
 require('../../modules/esnext.iterator.range');
 // TODO: Remove from `core-js@4`
 require('../../modules/esnext.iterator.as-indexed-pairs');

diff --git a/packages/core-js/internals/iterator-create-proxy.js b/packages/core-js/internals/iterator-create-proxy.js
@@ -46,7 +46,7 @@ var createIteratorProxyPrototype = function (IS_ITERATOR) {
       } catch (error) {
         return iteratorClose(iterator, 'throw', error);
       }
-      iteratorClose(iterator, 'normal');
+      if (iterator) iteratorClose(iterator, 'normal');
       return createIterResultObject(undefined, true);
     }
   });

diff --git a/packages/core-js/modules/esnext.iterator.concat.js b/packages/core-js/modules/esnext.iterator.concat.js
@@ -0,0 +1,56 @@
+'use strict';
+var $ = require('../internals/export');
+var call = require('../internals/function-call');
+var aCallable = require('../internals/a-callable');
+var anObject = require('../internals/an-object');
+var getIteratorMethod = require('../internals/get-iterator-method');
+var createIteratorProxy = require('../internals/iterator-create-proxy');
+
+var $Array = Array;
+
+var IteratorProxy = createIteratorProxy(function () {
+  while (true) {
+    var iterator = this.iterator;
+    if (!iterator) {
+      var iterableIndex = this.nextIterableIndex++;
+      var iterables = this.iterables;
+      if (iterableIndex >= iterables.length) {
+        this.done = true;
+        return;
+      }
+      var entry = iterables[iterableIndex];
+      this.iterables[iterableIndex] = null;
+      iterator = this.iterator = call(entry.method, entry.iterable);
+      this.next = iterator.next;
+    }
+    var result = anObject(call(this.next, iterator));
+    if (result.done) {
+      this.iterator = null;
+      this.next = null;
+      continue;
+    }
+    return result.value;
+  }
+});
+
+// `Iterator.concat` method
+// https://github.com/tc39/proposal-iterator-sequencing
+$({ target: 'Iterator', stat: true, forced: true }, {
+  concat: function concat() {
+    var length = arguments.length;
+    var iterables = $Array(length);
+    for (var index = 0; index < length; index++) {
+      var item = anObject(arguments[index]);
+      iterables[index] = {
+        iterable: item,
+        method: aCallable(getIteratorMethod(item))
+      };
+    }
+    return new IteratorProxy({
+      iterables: iterables,
+      nextIterableIndex: 0,
+      iterator: null,
+      next: null
+    });
+  }
+});
diff --git a/packages/core-js/proposals/iterator-sequencing.js b/packages/core-js/proposals/iterator-sequencing.js
@@ -0,0 +1,3 @@
+'use strict';
+// https://github.com/tc39/proposal-iterator-sequencing
+require('../modules/esnext.iterator.concat');
diff --git a/packages/core-js/stage/2.7.js b/packages/core-js/stage/2.7.js
@@ -1,4 +1,6 @@
 'use strict';
 var parent = require('./3');
 
+require('../proposals/iterator-sequencing');
+
 module.exports = parent;
diff --git a/tests/compat/tests.js b/tests/compat/tests.js
@@ -1677,6 +1677,9 @@ GLOBAL.tests = {
   'esnext.function.metadata': function () {
     return Function.prototype[Symbol.metadata] === null;
   },
+  'esnext.iterator.concat': function () {
+    return Iterator.concat;
+  },
   'esnext.iterator.dispose': function () {
     return [].keys()[Symbol.dispose];
   },

diff --git a/tests/entries/unit.mjs b/tests/entries/unit.mjs
@@ -771,6 +771,7 @@ for (PATH of ['core-js-pure', 'core-js']) {
     ok(load(NS, 'function/virtual/un-this').call([].slice)([1, 2, 3], 1)[0] === 2);
     ok(typeof load(NS, 'iterator/as-indexed-pairs') == 'function');
     ok(typeof load(NS, 'iterator/indexed') == 'function');
+    ok(load(NS, 'iterator/concat')([2]).next().value === 2);
     ok(load(NS, 'iterator/range')(1, 2).next().value === 1);
     ok(load(NS, 'map/delete-all')(new Map(), 1, 2) === false);
     ok(load(NS, 'map/emplace')(new Map([[1, 2]]), 1, { update: it => it ** 2 }) === 4);
@@ -938,6 +939,7 @@ for (PATH of ['core-js-pure', 'core-js']) {
   load('proposals/iterator-helpers-stage-3');
   load('proposals/iterator-helpers-stage-3-2');
   load('proposals/iterator-range');
+  load('proposals/iterator-sequencing');
   load('proposals/json-parse-with-source');
   load('proposals/keys-composition');
   load('proposals/map-update-or-insert');