JezK
Edit File: array-slice.js
// Copyright 2010 the V8 project authors. All rights reserved. // Redistribution and use in source and binary forms, with or without // modification, are permitted provided that the following conditions are // met: // // * Redistributions of source code must retain the above copyright // notice, this list of conditions and the following disclaimer. // * Redistributions in binary form must reproduce the above // copyright notice, this list of conditions and the following // disclaimer in the documentation and/or other materials provided // with the distribution. // * Neither the name of Google Inc. nor the names of its // contributors may be used to endorse or promote products derived // from this software without specific prior written permission. // // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. // Check that slicing array of holes keeps it as array of holes (function() { var array = new Array(10); for (var i = 0; i < 7; i++) { var sliced = array.slice(); assertEquals(array.length, sliced.length); assertFalse(0 in sliced); } })(); // Check various variants of empty array's slicing. (function() { for (var i = 0; i < 7; i++) { assertEquals([], [].slice(0, 0)); assertEquals([], [].slice(1, 0)); assertEquals([], [].slice(0, 1)); assertEquals([], [].slice(-1, 0)); } })(); // Check various forms of arguments omission. (function() { var array = new Array(7); for (var i = 0; i < 7; i++) { assertEquals(array, array.slice()); assertEquals(array, array.slice(0)); assertEquals(array, array.slice(undefined)); assertEquals(array, array.slice("foobar")); assertEquals(array, array.slice(undefined, undefined)); } })(); // Check variants of negatives and positive indices. (function() { var array = new Array(7); for (var i = 0; i < 7; i++) { assertEquals(7, array.slice(-100).length); assertEquals(3, array.slice(-3).length); assertEquals(3, array.slice(4).length); assertEquals(1, array.slice(6).length); assertEquals(0, array.slice(7).length); assertEquals(0, array.slice(8).length); assertEquals(0, array.slice(100).length); assertEquals(0, array.slice(0, -100).length); assertEquals(4, array.slice(0, -3).length); assertEquals(4, array.slice(0, 4).length); assertEquals(6, array.slice(0, 6).length); assertEquals(7, array.slice(0, 7).length); assertEquals(7, array.slice(0, 8).length); assertEquals(7, array.slice(0, 100).length); // Some exotic cases. obj = { toString: function() { throw 'Exception'; } }; // More than 2 arguments: assertEquals(7, array.slice(0, 7, obj, null, undefined).length); // Custom conversion: assertEquals(1, array.slice({valueOf: function() { return 1; }}, {toString: function() { return 2; }}).length); // Throwing an exception in conversion: try { assertEquals(7, array.slice(0, obj).length); throw 'Should have thrown'; } catch (e) { assertEquals('Exception', e); } } })(); // Nasty: modify the array in ToInteger. (function() { var array = []; var expected = [] bad_guy = { valueOf: function() { array.push(array.length); return -1; } }; for (var i = 0; i < 13; i++) { var sliced = array.slice(bad_guy); expected.push(i); assertEquals(expected, array); // According to the spec (15.4.4.10), length is calculated before // performing ToInteger on arguments. if (i == 0) { assertEquals([], sliced); // Length was 0, nothing to get. } else { // Actually out of array [0..i] we get [i - 1] as length is i. assertEquals([i - 1], sliced); } } })(); // Now check the case with array of holes and some elements on prototype. // Note: that is important that this test runs before the next one // as the next one tampers Array.prototype. (function() { var len = 9; var array = new Array(len); var at3 = "@3"; var at7 = "@7"; for (var i = 0; i < 7; i++) { var array_proto = []; array_proto[3] = at3; array_proto[7] = at7; array.__proto__ = array_proto; assertEquals(len, array.length); for (var i = 0; i < array.length; i++) { assertEquals(array[i], array_proto[i]); } var sliced = array.slice(); assertEquals(len, sliced.length); assertTrue(delete array_proto[3]); assertTrue(delete array_proto[7]); // Note that slice copies values from prototype into the array. assertEquals(array[3], undefined); assertFalse(array.hasOwnProperty(3)); assertEquals(sliced[3], at3); assertTrue(sliced.hasOwnProperty(3)); assertEquals(array[7], undefined); assertFalse(array.hasOwnProperty(7)); assertEquals(sliced[7], at7); assertTrue(sliced.hasOwnProperty(7)); // ... but keeps the rest as holes: array_proto[5] = "@5"; assertEquals(array[5], array_proto[5]); assertFalse(array.hasOwnProperty(5)); } })(); // Now check the case with array of holes and some elements on prototype. (function() { var len = 9; var array = new Array(len); var at3 = "@3"; var at7 = "@7"; for (var i = 0; i < 7; i++) { Array.prototype[3] = at3; Array.prototype[7] = at7; assertEquals(len, array.length); for (var i = 0; i < array.length; i++) { assertEquals(array[i], Array.prototype[i]); } var sliced = array.slice(); assertEquals(len, sliced.length); assertTrue(delete Array.prototype[3]); assertTrue(delete Array.prototype[7]); // Note that slice copies values from prototype into the array. assertEquals(array[3], undefined); assertFalse(array.hasOwnProperty(3)); assertEquals(sliced[3], at3); assertTrue(sliced.hasOwnProperty(3)); assertEquals(array[7], undefined); assertFalse(array.hasOwnProperty(7)); assertEquals(sliced[7], at7); assertTrue(sliced.hasOwnProperty(7)); // ... but keeps the rest as holes: Array.prototype[5] = "@5"; assertEquals(array[5], Array.prototype[5]); assertFalse(array.hasOwnProperty(5)); assertEquals(sliced[5], Array.prototype[5]); assertFalse(sliced.hasOwnProperty(5)); assertTrue(delete Array.prototype[5]); } })(); // Check slicing on arguments object. (function() { function func(expected, a0, a1, a2) { assertEquals(expected, Array.prototype.slice.call(arguments, 1)); } func([]); func(['a'], 'a'); func(['a', 1], 'a', 1); func(['a', 1, undefined], 'a', 1, undefined); func(['a', 1, undefined, void(0)], 'a', 1, undefined, void(0)); })(); // Check slicing on arguments object when missing arguments get assigined. (function() { function func(x, y) { assertEquals(1, arguments.length); assertEquals(undefined, y); y = 239; assertEquals(1, arguments.length); // arguments length is the same. assertEquals([x], Array.prototype.slice.call(arguments, 0)); } func('a'); })(); // Check slicing on arguments object when length property has been set. (function() { function func(x, y) { assertEquals(1, arguments.length); arguments.length = 7; assertEquals([x,,,,,,,], Array.prototype.slice.call(arguments, 0)); } func('a'); })(); // Check slicing on arguments object when length property has been set to // some strange value. (function() { function func(x, y) { assertEquals(1, arguments.length); arguments.length = 'foobar'; assertEquals([], Array.prototype.slice.call(arguments, 0)); } func('a'); })(); // Check slicing on arguments object when extra argument has been added // via indexed assignment. (function() { function func(x, y) { assertEquals(1, arguments.length); arguments[3] = 239; assertEquals([x], Array.prototype.slice.call(arguments, 0)); } func('a'); })(); // Check slicing on arguments object when argument has been deleted by index. (function() { function func(x, y, z) { assertEquals(3, arguments.length); delete arguments[1]; assertEquals([x,,z], Array.prototype.slice.call(arguments, 0)); } func('a', 'b', 'c'); })();