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 reg exp includes: [compareArray.js] features: [Symbol.isConcatSpreadable] ---*/ var re = /abc/; // RegExps are not concat-spreadable by default assert.compareArray([].concat(re), [re], '[].concat(/abc/) must return [re]'); // RegExps may be individually concat-spreadable re[Symbol.isConcatSpreadable] = true; re[0] = 1, re[1] = 2, re[2] = 3, re.length = 3; assert.compareArray([].concat(re), [1, 2, 3], '[].concat(/abc/) must return [1, 2, 3]'); // RegExps may be concat-spreadable RegExp.prototype[Symbol.isConcatSpreadable] = true; RegExp.prototype.length = 3; assert.compareArray([].concat(/abc/), [void 0, void 0, void 0], '[].concat(/abc/) must return [void 0, void 0, void 0]' ); RegExp.prototype[0] = 1; RegExp.prototype[1] = 2; RegExp.prototype[2] = 3; assert.compareArray([].concat(/abc/), [1, 2, 3], '[].concat(/abc/) must return [1, 2, 3]' ); delete RegExp.prototype[Symbol.isConcatSpreadable]; delete RegExp.prototype[0]; delete RegExp.prototype[1]; delete RegExp.prototype[2]; delete RegExp.prototype.length;