// Tests for Array#copyWithin load(libdir + "asserts.js"); assertEq(Array.prototype.copyWithin.length, 2); // works with two arguments assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, 3), [4, 5, 3, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(1, 3), [1, 4, 5, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(1, 2), [1, 3, 4, 5, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(2, 2), [1, 2, 3, 4, 5]); // works with three arguments assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, 3, 4), [4, 2, 3, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(1, 3, 4), [1, 4, 3, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(1, 2, 4), [1, 3, 4, 4, 5]); // works with negative arguments assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, -2), [4, 5, 3, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, -2, -1), [4, 2, 3, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(-4, -3, -2), [1, 3, 3, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(-4, -3, -1), [1, 3, 4, 4, 5]); assertDeepEq([1, 2, 3, 4, 5].copyWithin(-4, -3), [1, 3, 4, 5, 5]); // works with array-like objects var args = (function () { return Array.prototype.slice.call(arguments); }(1, 2, 3)); var argsClass = Object.prototype.toString.call(args); assertDeepEq(args, [1, 2, 3]); Array.prototype.copyWithin.call(args, -2, 0); assertDeepEq(args, [1, 1, 2]); assertDeepEq(Object.prototype.toString.call(args), argsClass); // throws on null/undefined values assertThrowsInstanceOf(function() { Array.prototype.copyWithin.call(null, 0, 3); }, TypeError, "Assert that copyWithin fails if this value is null"); assertThrowsInstanceOf(function() { Array.prototype.copyWithin.call(undefined, 0, 3); }, TypeError, "Assert that copyWithin fails if this value is undefined"); // test with this value as string assertThrowsInstanceOf(function() { Array.prototype.copyWithin.call("hello world", 0, 3); }, TypeError, "Assert that copyWithin fails if this value is string"); // test with this value as number assertDeepEq(Array.prototype.copyWithin.call(34, 0, 3), new Number(34)); // test with this value as TypedArray var buffer = new ArrayBuffer(16); var int32View = new Int32Array(buffer); for (var i=0; i<int32View.length; i++) { int32View[i] = i*2; } assertDeepEq(Array.prototype.copyWithin.call(int32View, 0, 1), new Int32Array([2, 4, 6, 6])); // if arguments object is sloppy, copyWithin must move the arguments around function f(a, b, c, d, e) { [].copyWithin.call(arguments, 1, 3); return [a, b, c, d, e]; } assertDeepEq(f(1, 2, 3, 4, 5), [1, 4, 5, 4, 5]); // test with target > start on 2 arguments assertDeepEq([1, 2, 3, 4, 5].copyWithin(3, 0), [1, 2, 3, 1, 2]); // test with target > start on 3 arguments assertDeepEq([1, 2, 3, 4, 5].copyWithin(3, 0, 4), [1, 2, 3, 1, 2]); // test on array with holes var arr = new Array(6); for (var i = 0; i < arr.length; i += 2) { arr[i] = i; } assertDeepEq(arr.copyWithin(0, 3), [, 4, , , 4, , ]); // test on fractional arguments assertDeepEq([1, 2, 3, 4, 5].copyWithin(0.2, 3.9), [4, 5, 3, 4, 5]); // test with -0 assertDeepEq([1, 2, 3, 4, 5].copyWithin(-0, 3), [4, 5, 3, 4, 5]); // test with arguments more than this.length assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, 7), [1, 2, 3, 4, 5]); // test with arguments less than -this.length assertDeepEq([1, 2, 3, 4, 5].copyWithin(-7, 0), [1, 2, 3, 4, 5]); // test with arguments equal to -this.length assertDeepEq([1, 2, 3, 4, 5].copyWithin(-5, 0), [1, 2, 3, 4, 5]); // test on empty array assertDeepEq([].copyWithin(0, 3), []); // test with target range being shorter than end - start assertDeepEq([1, 2, 3, 4, 5].copyWithin(2, 1, 4), [1, 2, 2, 3, 4]); // test overlapping ranges arr = [1, 2, 3, 4, 5]; arr.copyWithin(2, 1, 4); assertDeepEq(arr.copyWithin(2, 1, 4), [1, 2, 2, 2, 3]); // check that delete is strict arr = [1, , 3, , 4, 5]; Object.freeze(arr); assertThrowsInstanceOf(function() { arr.copyWithin(2, 1, 4); }, TypeError, "Assert that delete is strict in copyWithin"); // test with a proxy object var proxyObj = { get: function(recipient, name) { return recipient[name] + 2; } }; var p = new Proxy([1, 2, 3, 4, 5], proxyObj); Array.prototype.copyWithin.call(p, 0, 3); for (name of Object.getOwnPropertyNames(p)) { print(name + ": " + uneval(Object.getOwnPropertyDescriptor(p, name))); } assertDeepEq(p, [6, 7, , , 5]); // test if we throw in between arr = [1, 2, 3, 4, 5]; Object.defineProperty(arr, 1, { set: function () { throw new Error("Boom!"); } }); assertThrowsInstanceOf(function() { arr.copyWithin(1, 3); }, Error, "Throwing in between."); assertEq(arr[0], 1); assertEq(arr[1], undefined); assertEq(arr[2], 3); assertEq(arr[3], 4); assertEq(arr[4], 5); // undefined as third argument assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, 3, undefined), [4, 5, 3, 4, 5]); // test that this.length is called only once arr = {0: 1, 1: 2, 2: 3, 3: 4, 4: 5}; var count = 0; Object.defineProperty(arr, "length", { get: function () { count++; } }); Array.prototype.copyWithin.call(arr, 1, 3); assertEq(count, 1); count = 0; Array.prototype.copyWithin.call(arr, 1, 3, 4); assertEq(count, 1); var large = 10000; // test on a large array arr = new Array(large); assertDeepEq(arr.copyWithin(45, 900), arr); // test on floating point numbers for (var i = 0; i < large; i++) { arr[i] = Math.random(); } arr.copyWithin(45, 900); // test on array of objects for (var i = 0; i < large; i++) { arr[i] = { num: Math.random() }; } arr.copyWithin(45, 900); // test array length remains same assertEq(arr.length, large); // test null on third argument is handled correctly assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, 3, null), [1, 2, 3, 4, 5]); // tamper the global Object prototype and test this works Object.prototype[2] = 1; assertDeepEq([1, 2, 3, 4, 5].copyWithin(0, 3), [4, 5, 3, 4, 5]);