| var wellKnownSymbol = require('../internals/well-known-symbol'); |
| var create = require('../internals/object-create'); |
| var createNonEnumerableProperty = require('../internals/create-non-enumerable-property'); |
| |
| var UNSCOPABLES = wellKnownSymbol('unscopables'); |
| var ArrayPrototype = Array.prototype; |
| |
| // Array.prototype[@@unscopables] |
| // https://tc39.github.io/ecma262/#sec-array.prototype-@@unscopables |
| if (ArrayPrototype[UNSCOPABLES] == undefined) { |
| createNonEnumerableProperty(ArrayPrototype, UNSCOPABLES, create(null)); |
| } |
| |
| // add a key to Array.prototype[@@unscopables] |
| module.exports = function (key) { |
| ArrayPrototype[UNSCOPABLES][key] = true; |
| }; |