JSTests/ChakraCore/test/typedarray/TypedArrayBuiltins.js

//-------------------------------------------------------------------------------------------------------
// Copyright (C) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE.txt file in the project root for full license information.
//-------------------------------------------------------------------------------------------------------

// Verifies TypedArray builtin properties

if (this.WScript && this.WScript.LoadScriptFile) { // Check for running in ch
    this.WScript.LoadScriptFile("..\\UnitTestFramework\\UnitTestFramework.js");
}

function mangle(u8) {
    u8.length = -2;
    u8.byteLength = 2000;
    u8.byteOffset = 45;
    u8.buffer = 25;
    u8.BYTES_PER_ELEMENT = 4;
}

var tests = [
    {
        name: "TypedArray builtin properties can't be overwritten, but writing to them does not throw an error",
        body: function () {
            var arr = new ArrayBuffer(100);
            var u8 = new Uint8Array(arr, 90);

            for (var i = 0; i < u8.length; i++) {
                u8[i] = i;
            }

            mangle(u8);

            assert.areEqual(10, u8.length, "Writing to length has no effect");
            assert.areEqual(10, u8.byteLength, "Writing to byteLength has no effect");
            assert.areEqual(90, u8.byteOffset, "Writing to byteOffset has no effect");
            assert.areEqual(1, u8.BYTES_PER_ELEMENT, "Writing to BYTES_PER_ELEMENT has no effect");
            assert.isTrue(arr === u8.buffer, "Writing to buffer has no effect");

            assert.throws(function() { Array.prototype.splice.call(u8, 4, 3, 1, 2, 3, 4, 5); }, TypeError, "Array.prototype.splice tries to set the length property of the TypedArray object which will throw", "Cannot define property: object is not extensible");
            assert.areEqual(10, u8.length, "Array.prototype.splice throws when it tries to set the length property");
            assert.areEqual(10, u8.byteLength, "The byteLength property should not be changed");
            assert.areEqual([0,1,2,3,1,2,3,4,5,7], u8, "After splice, array has correct values - NOTE: last two values are gone from the array");

            assert.throws(function() { Array.prototype.push.call(u8, 100); }, TypeError, "Array.prototype.push tries to set the length property of the TypedArray object which will throw", "Cannot define property: object is not extensible");
            assert.areEqual([0,1,2,3,1,2,3,4,5,7], u8, "Array.prototype.push doesn't modify the TypedArray");
        }
    },
    {
        name: "TypedArray constructed out of an iterable object",
        body: function () {
            function getIterableObj (array)
            {
                return {
                    [Symbol.iterator]: ()=> {
                        return {
                            next: () => {
                                return {
                                    value: array.shift(),
                                    done: array.length == 0
                                };
                            }
                        };
                    }
                };
            }

            function getIterableObjNextDesc (array)
            {
                return  {
                    get: function () {
                        array.shift(); // side effect
                        return function () {
                            return {
                                value: array.shift(),
                                done:  array.length == 0
                            };
                        };
                    }
                };
            }

            var TypedArray = [
                'Int8Array',
                'Uint8Array',
                'Uint8ClampedArray',
                'Int16Array',
                'Uint16Array',
                'Int32Array',
                'Uint32Array',
                'Float32Array',
                'Float64Array'
            ];

            for(var t of TypedArray) {
                var arr = new this[t](getIterableObj([1,2,3,4]));
                assert.areEqual(3, arr.length, "TypedArray " + t + " created from iterable has length == 3");
                assert.areEqual(1, arr[0], "TypedArray " + t + " created from iterable has element #0 == 1");
                assert.areEqual(2, arr[1], "TypedArray " + t + " created from iterable has element #1 == 2");
                assert.areEqual(3, arr[2], "TypedArray " + t + " created from iterable has element #2 == 3");
            }

            // change array's iterator
            (function() {
                for(var t of TypedArray) {
                    var a = [1,2,3,4];
                    a[Symbol.iterator] = getIterableObj([99,0])[Symbol.iterator];
                    var arr = new this[t](a);
                    assert.areEqual(1, arr.length, "TypedArray " + t + " created from array with user-defined iterator has length == 1");
                    assert.areEqual(99, arr[0], "TypedArray " + t + " created from array with user-defined iterator has element #0 == 99");
                }
            })();

            // helpers for testing all typed arrays when built-in array iterator is changed
            function testTypedArrayConstructorWithIterableArray(inputarray, t, func, text) {
                func();
                var arr = new this[t](inputarray);
                assert.areEqual(1, arr.length, "TypedArray " + t + " created from array with " + text + " has length == 1");
                assert.areEqual(99, arr[0], "TypedArray " + t + " created from array with "+ text + " has element #0 == 99");
            }
            function testAllTypedArrayConstructorsWithIterableArray(inputarray, func, text) {
                testTypedArrayConstructorWithIterableArray(inputarray, 'Int8Array', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Uint8Array', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Uint8ClampedArray', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Int16Array', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Uint16Array', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Int32Array', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Uint32Array', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Float32Array', func, text);
                testTypedArrayConstructorWithIterableArray(inputarray, 'Float64Array', func, text);
            }

            // change built-in Array prototype's iterator
            (function() {
                var builtinArrayPrototypeIteratorDesc = Object.getOwnPropertyDescriptor(Array.prototype, Symbol.iterator);
                var a = [1,2,3,4];
                Object.defineProperty(Array.prototype, Symbol.iterator, {enumerable: false, configurable: true, writable: true});

                var overrideBuiltinArrayPrototypeIterator = function() {
                    Array.prototype[Symbol.iterator] = getIterableObj([99,0])[Symbol.iterator];
                };
                testAllTypedArrayConstructorsWithIterableArray(a, overrideBuiltinArrayPrototypeIterator, "Array.prototype overriden");
                Object.defineProperty(Array.prototype, Symbol.iterator, builtinArrayPrototypeIteratorDesc);
            })();

            // change built-in array iterator's next function
            (function() {
                var arrayIteratorProto = Object.getPrototypeOf([][Symbol.iterator]());
                var builtinArrayPrototypeIteratorNext = arrayIteratorProto.next;
                var overrideBuiltinArrayIteratorNext = function() {
                    arrayIteratorProto.next = getIterableObj([99,0])[Symbol.iterator]().next;
                }
                var a = [1,2,3,4];
                testAllTypedArrayConstructorsWithIterableArray(a, overrideBuiltinArrayIteratorNext, "%ArrayIteratorPrototype%.next overriden");
                arrayIteratorProto.next = builtinArrayPrototypeIteratorNext;
            })();

            // change built-in array iterator's next getter function
            (function() {
                var arrayIteratorProto = Object.getPrototypeOf([][Symbol.iterator]());
                var builtinArrayPrototypeIteratorNextDesc = Object.getOwnPropertyDescriptor(arrayIteratorProto, "next");
                var overrideBuiltinArrayIteratorNext = function() {
                    Object.defineProperty(arrayIteratorProto, "next", getIterableObjNextDesc([0,99,0]));
                }
                var a = [1,2,3,4];
                testAllTypedArrayConstructorsWithIterableArray(a, overrideBuiltinArrayIteratorNext, "%ArrayIteratorPrototype%.next overriden by getter");
                Object.defineProperty(arrayIteratorProto, "next", builtinArrayPrototypeIteratorNextDesc);
            })();
        }
    },
    {
        name: "TypedArray constructor and TypedArray.from don't get @@iterator twice",
        body: function () {
            let count = 0;
            new Uint8Array({
                get [Symbol.iterator]() {
                    count++;
                    return [][Symbol.iterator];
                }
            });
            assert.areEqual(count, 1, "TypedArray constructor calls @@iterator getter once");

            count = 0;
            new Uint8Array(new Proxy({}, {
                get(target, property) {
                    if (property === Symbol.iterator) {
                        count++;
                        return [][Symbol.iterator];
                    }
                    return Reflect.get(target, property);
                }
            }));
            assert.areEqual(count, 1, "TypedArray constructor calls proxy's getter with @@iterator as parameter only once");

            count = 0;
            Uint8Array.from({
                get [Symbol.iterator]() {
                    count++;
                    return [][Symbol.iterator];
                }
            });
            assert.areEqual(count, 1, "TypedArray.from calls @@iterator getter once");

            count = 0;
            Uint8Array.from(new Proxy({}, {
                get(target, property) {
                    if (property === Symbol.iterator) {
                        count++;
                        return [][Symbol.iterator];
                    }
                    return Reflect.get(target, property);
                }
            }));
            assert.areEqual(count, 1, "TypedArray.from calls proxy's getter with @@iterator as parameter only once");
        }
    }
];

testRunner.runTests(tests, { verbose: WScript.Arguments[0] != "summary" });