add Symbol.metadata

Author: zloirock

README.md

@@ -2049,6 +2049,18 @@ Object.hasOwn({ foo: 42 }, 'foo'); // => true
 Object.hasOwn({ foo: 42 }, 'bar'); // => false
 Object.hasOwn({}, 'toString');     // => false
 ````
+##### [`Symbol.metadata` for decorators proposal](https://github.com/tc39/proposal-decorators)[⬆](#index)
+Module [`esnext.symbol.metadata`](https://github.com/zloirock/core-js/blob/master/packages/core-js/modules/esnext.symbol.metadata.js).
+```js
+class Symbol {
+  static metadata: @@metadata;
+}
+```
+[*CommonJS entry points:*](#commonjs-api)
+```js
+core-js/proposals/decorators
+core-js(-pure)/features/symbol/metadata
+```
 
 #### Stage 1 proposals[⬆](#index)
 [*CommonJS entry points:*](#commonjs-api)

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

@@ -1504,6 +1504,8 @@ const data = {
   },
   'esnext.symbol.dispose': {
   },
+  'esnext.symbol.metadata': {
+  },
   'esnext.symbol.observable': {
   },
   'esnext.symbol.pattern-match': {

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

@@ -83,4 +83,7 @@ module.exports = {
   3.11: [
     'esnext.object.has-own',
   ],
+  3.12: [
+    'esnext.symbol.metadata',
+  ],
 };

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

@@ -1,6 +1,7 @@
 var parent = require('../../es/symbol');
 require('../../modules/esnext.symbol.async-dispose');
 require('../../modules/esnext.symbol.dispose');
+require('../../modules/esnext.symbol.metadata');
 require('../../modules/esnext.symbol.observable');
 require('../../modules/esnext.symbol.pattern-match');
 // TODO: Remove from `core-js@4`

packages/core-js/features/symbol/metadata.js

@@ -0,0 +1,4 @@
+require('../../modules/esnext.symbol.metadata');
+var WrappedWellKnownSymbolModule = require('../../internals/well-known-symbol-wrapped');
+
+module.exports = WrappedWellKnownSymbolModule.f('metadata');

packages/core-js/modules/esnext.symbol.metadata.js

@@ -0,0 +1,5 @@
+var defineWellKnownSymbol = require('../internals/define-well-known-symbol');
+
+// `Symbol.metadata` well-known symbol
+// https://github.com/tc39/proposal-decorators
+defineWellKnownSymbol('metadata');

packages/core-js/proposals/decorators.js

@@ -0,0 +1,2 @@
+// https://github.com/tc39/proposal-decorators
+require('../modules/esnext.symbol.metadata');

packages/core-js/proposals/pattern-matching.js

@@ -1 +1,2 @@
+// https://github.com/tc39/proposal-pattern-matching
 require('../modules/esnext.symbol.pattern-match');

packages/core-js/stage/2.js

@@ -1,6 +1,7 @@
 require('../proposals/accessible-object-hasownproperty');
 require('../proposals/array-find-from-last');
 require('../proposals/array-is-template-object');
+require('../proposals/decorators');
 require('../proposals/iterator-helpers');
 require('../proposals/map-upsert');
 require('../proposals/set-methods');

tests/commonjs.js

@@ -55,7 +55,6 @@ for (PATH of ['core-js-pure', 'core-js']) {
   }, 1, 2)(3) === 6);
   load('features/function/name');
   load('features/function/has-instance');
-  ok(Function[load('features/symbol/has-instance')](it => it));
   ok('bind' in load('features/function'));
   ok(load('features/array/is-array')([]));
   ok(typeof load('features/array/is-template-object') === 'function');
@@ -299,6 +298,7 @@ for (PATH of ['core-js-pure', 'core-js']) {
   ok(load('features/symbol/iterator'));
   ok(load('features/symbol/match'));
   ok(load('features/symbol/match-all'));
+  ok(load('features/symbol/metadata'));
   ok(load('features/symbol/replace'));
   ok(load('features/symbol/search'));
   ok(load('features/symbol/species'));
@@ -972,6 +972,7 @@ for (PATH of ['core-js-pure', 'core-js']) {
   load('proposals/array-unique');
   load('proposals/collection-methods');
   load('proposals/collection-of-from');
+  load('proposals/decorators');
   load('proposals/efficient-64-bit-arithmetic');
   load('proposals/global-this');
   load('proposals/iterator-helpers');

tests/compat/tests.js

@@ -1431,6 +1431,9 @@ GLOBAL.tests = {
   'esnext.symbol.dispose': function () {
     return Symbol.dispose;
   },
+  'esnext.symbol.metadata': function () {
+    return Symbol.metadata;
+  },
   'esnext.symbol.observable': function () {
     return Symbol.observable;
   },

tests/pure/esnext.symbol.metadata.js

@@ -0,0 +1,6 @@
+import Symbol from 'core-js-pure/features/symbol';
+
+QUnit.test('Symbol.metadata', assert => {
+  assert.ok('metadata' in Symbol, 'Symbol.metadata available');
+  assert.ok(Object(Symbol.metadata) instanceof Symbol, 'Symbol.metadata is symbol');
+});

tests/tests/esnext.symbol.metadata.js

@@ -0,0 +1,13 @@
+import { DESCRIPTORS } from '../helpers/constants';
+
+QUnit.test('Symbol.metadata', assert => {
+  assert.ok('metadata' in Symbol, 'Symbol.metadata available');
+  assert.nonEnumerable(Symbol, 'metadata');
+  assert.ok(Object(Symbol.metadata) instanceof Symbol, 'Symbol.metadata is symbol');
+  if (DESCRIPTORS) {
+    const descriptor = Object.getOwnPropertyDescriptor(Symbol, 'metadata');
+    assert.ok(!descriptor.enumerble, 'non-enumerable');
+    assert.ok(!descriptor.writable, 'non-writable');
+    assert.ok(!descriptor.configurable, 'non-configurable');
+  }
+});