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