array-species-create.js
714 Bytes
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.es/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);
};