JezK
Edit File: double-equals.js
// Copyright 2008 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. /** * This test uses assert{True,False}(... == ...) instead of * assertEquals(..., ...) to not rely on the details of the * implementation of assertEquals. */ function testEqual(a, b) { assertTrue(a == b); assertTrue(b == a); assertFalse(a != b); assertFalse(b != a); } function testNotEqual(a, b) { assertFalse(a == b); assertFalse(b == a); assertTrue(a != b); assertTrue(b != a); } // Object where ToPrimitive returns value. function Wrapper(value) { this.value = value; this.valueOf = function () { return this.value; }; } // Object where ToPrimitive returns value by failover to toString when // valueOf isn't a function. function Wrapper2(value) { this.value = value; this.valueOf = null; this.toString = function () { return this.value; }; } // Compare values of same type. // Numbers are equal if same, unless NaN, which isn't equal to anything, and // +/-0 being equal. testNotEqual(NaN, NaN); testNotEqual(NaN, 0); testNotEqual(NaN, Infinity); testEqual(Number.MAX_VALUE, Number.MAX_VALUE); testEqual(Number.MIN_VALUE, Number.MIN_VALUE); testEqual(Infinity, Infinity); testEqual(-Infinity, -Infinity); testEqual(0, 0); testEqual(0, -0); testEqual(-0, -0); testNotEqual(0.9, 1); testNotEqual(0.999999, 1); testNotEqual(0.9999999999, 1); testNotEqual(0.9999999999999, 1); // Strings are equal if containing the same code points. testEqual('hello', 'hello'); testEqual('hello', 'hel' + 'lo'); testEqual('', ''); testEqual('\u0020\x20', ' '); // Escapes are not part of the value. // Booleans are equal if they are the same. testEqual(true, true); testEqual(false, false); testNotEqual(true, false); // Null and undefined are equal to themselves. testEqual(null, null); testEqual(undefined, undefined); // Objects are equal if they are the same object only. testEqual(Math, Math); testEqual(Object.prototype, Object.prototype); (function () { var x = new Wrapper(null); var y = x, z = x; testEqual(y, x); })(); (function () { var x = new Boolean(true); var y = x, z = x; testEqual(y, x); })(); (function () { var x = new Boolean(false); var y = x, z = x; testEqual(y, x); })(); // Test comparing values of different types. // Null and undefined are equal to each-other, and to nothing else. testEqual(null, undefined); testEqual(undefined, null); testNotEqual(null, new Wrapper(null)); testNotEqual(null, 0); testNotEqual(null, false); testNotEqual(null, ""); testNotEqual(null, new Object()); testNotEqual(undefined, new Wrapper(undefined)); testNotEqual(undefined, 0); testNotEqual(undefined, false); testNotEqual(undefined, ""); testNotEqual(undefined, new Object()); // Numbers compared to Strings will convert the string to a number using // the internal ToNumber conversion. testEqual(1, '1'); testEqual(255, '0xff'); testEqual(0, '\r'); // ToNumber ignores tailing and trailing whitespace. testEqual(1e19, '1e19'); testEqual(Infinity, "Infinity"); // Booleans compared to anything else will be converted to numbers. testEqual(false, 0); testEqual(true, 1); testEqual(false, "0"); // String also converted to number. testEqual(true, "1"); // Objects compared to Number or String (or Boolean, since that's converted // to Number too) is converted to primitive using ToPrimitive with NO HINT. // Having no hint means Date gets a string hint, and everything else gets // a number hint. testEqual(new Boolean(true), true); testEqual(new Boolean(true), 1); // First to primtive boolean, then to number. testEqual(new Boolean(false), false); testEqual(new Boolean(false), 0); testEqual(new Wrapper(true), true); testEqual(new Wrapper(true), 1); testEqual(new Wrapper(false), false); testEqual(new Wrapper(false), 0); testEqual(new Wrapper2(true), true); testEqual(new Wrapper2(true), 1); testEqual(new Wrapper2(false), false); testEqual(new Wrapper2(false), 0); testEqual(new Number(1), true); testEqual(new Number(1), 1); testEqual(new Number(0), false); testEqual(new Number(0), 0); // Date objects convert to string, not number (and the string does not // convert to the number). testEqual(new Date(42), String(new Date(42))); testNotEqual(new Date(42), Number(new Date(42))); var dnow = new Date(); testEqual(dnow, dnow); testEqual(dnow, String(dnow)); testNotEqual(dnow, Number(dnow)); // Doesn't just call toString, but uses ToPrimitive which tries toString first // and valueOf second. dnow.toString = null; testEqual(dnow, Number(dnow)); dnow.valueOf = function () { return "42"; }; testEqual(dnow, 42); dnow.toString = function () { return "1"; }; testEqual(dnow, true); // Objects compared to other objects, or to null and undefined, are not // converted to primitive. testNotEqual(new Wrapper(null), new Wrapper(null)); testNotEqual(new Boolean(true), new Boolean(true)); testNotEqual(new Boolean(false), new Boolean(false)); testNotEqual(new String("a"), new String("a")); testNotEqual(new Number(42), new Number(42)); testNotEqual(new Date(42), new Date(42)); testNotEqual(new Array(42), new Array(42)); testNotEqual(new Object(), new Object()); // Object that can't be converted to primitive. var badObject = { valueOf: null, toString: function() { return this; // Not primitive. } }; testEqual(badObject, badObject); testNotEqual(badObject, {}); testNotEqual(badObject, null); testNotEqual(badObject, undefined); // Forcing conversion will throw. function testBadConversion(value) { assertThrows(function() { return badObject == value; }); assertThrows(function() { return badObject != value; }); assertThrows(function() { return value == badObject; }); assertThrows(function() { return value != badObject; }); } testBadConversion(0); testBadConversion("string"); testBadConversion(true);