22 lines
669 B
JavaScript
22 lines
669 B
JavaScript
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'use strict';
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var wellKnownSymbol = require('../internals/well-known-symbol');
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var create = require('../internals/object-create');
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var defineProperty = require('../internals/object-define-property').f;
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var UNSCOPABLES = wellKnownSymbol('unscopables');
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var ArrayPrototype = Array.prototype;
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// Array.prototype[@@unscopables]
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// https://tc39.es/ecma262/#sec-array.prototype-@@unscopables
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if (ArrayPrototype[UNSCOPABLES] === undefined) {
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defineProperty(ArrayPrototype, UNSCOPABLES, {
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configurable: true,
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value: create(null)
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});
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}
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// add a key to Array.prototype[@@unscopables]
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module.exports = function (key) {
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ArrayPrototype[UNSCOPABLES][key] = true;
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};
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