| var isObject = require('../internals/is-object'); |
| var isArray = require('../internals/is-array'); |
| var wellKnownSymbol = require('../internals/well-known-symbol'); |
| |
| var SPECIES = wellKnownSymbol('species'); |
| |
| // `ArraySpeciesCreate` abstract operation |
| // https://tc39.github.io/ecma262/#sec-arrayspeciescreate |
| module.exports = function (originalArray, length) { |
| var C; |
| if (isArray(originalArray)) { |
| C = originalArray.constructor; |
| // cross-realm fallback |
| if (typeof C == 'function' && (C === Array || isArray(C.prototype))) C = undefined; |
| else if (isObject(C)) { |
| C = C[SPECIES]; |
| if (C === null) C = undefined; |
| } |
| } return new (C === undefined ? Array : C)(length === 0 ? 0 : length); |
| }; |