// Copyright JS Foundation and other contributors, http://js.foundation // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // Test with regular arrays var alpha = ['a', 'b', 'c']; var numeric = [1, 2, 3]; var alphaNumeric = alpha.concat(numeric); assert(JSON.stringify(alphaNumeric) === '["a","b","c",1,2,3]'); assert(alphaNumeric.length === 6); numeric[Symbol.isConcatSpreadable] = false; alphaNumeric = alpha.concat(numeric); assert(JSON.stringify(alphaNumeric) === '["a","b","c",[1,2,3]]'); assert(alphaNumeric.length === 4); numeric[Symbol.isConcatSpreadable] = true; // Test with array-like object var fakeArray = { [Symbol.isConcatSpreadable]: true, length: 2, 0: 4, 1: 5 } var numericArray = numeric.concat(fakeArray); assert(JSON.stringify(numericArray) === '[1,2,3,4,5]'); assert(numericArray.length === 5); fakeArray[Symbol.isConcatSpreadable] = false; numericArray = numeric.concat(fakeArray); assert(JSON.stringify(numericArray) === '[1,2,3,{"0":4,"1":5,"length":2}]'); assert(numericArray.length === 4); // Test with object var obj = { 0: 'd' }; var alphaObj = alpha.concat(obj); assert(JSON.stringify(alphaObj) === '["a","b","c",{"0":"d"}]'); assert(alphaObj.length === 4); obj[Symbol.isConcatSpreadable] = true; alphaObj = alpha.concat(obj); assert(JSON.stringify(alphaObj) === '["a","b","c"]'); assert(alphaObj.length === 3); // Test with boolean var bool = true; var numericBool = numeric.concat(bool); assert(JSON.stringify(numericBool) === '[1,2,3,true]'); assert(numericBool.length === 4); bool[Symbol.isConcatSpreadable] = false; numericBool = numeric.concat(bool); assert(JSON.stringify(numericBool) === '[1,2,3,true]'); assert(numericBool.length === 4); // Test when unable to concat var array1 = []; var array2 = []; Object.defineProperty(array2, '0', { 'get' : function () {throw new ReferenceError ("foo"); } }); try { array1.concat(array2); assert(false); } catch (e) { assert(e.message === "foo"); assert(e instanceof ReferenceError); }