Strict mode Passingnon-Strict mode Passing
Features:
- Symbol.isConcatSpreadable
// Copyright (c) 2014 the V8 project authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. /*--- esid: sec-array.prototype.concat description: Array.prototype.concat Symbol.isConcatSpreadable sparse object includes: [compareArray.js] features: [Symbol.isConcatSpreadable] ---*/ var obj = { length: 5 }; obj[Symbol.isConcatSpreadable] = true; assert.compareArray([void 0, void 0, void 0, void 0, void 0], [].concat(obj), '[void 0, void 0, void 0, void 0, void 0] must return the same value returned by [].concat(obj)' ); obj.length = 4000; assert.compareArray(new Array(4000), [].concat(obj), 'new Array(4000) must return the same value returned by [].concat(obj)' );