1// Copyright 2010 the V8 project authors. All rights reserved. 2// Redistribution and use in source and binary forms, with or without 3// modification, are permitted provided that the following conditions are 4// met: 5// 6// * Redistributions of source code must retain the above copyright 7// notice, this list of conditions and the following disclaimer. 8// * Redistributions in binary form must reproduce the above 9// copyright notice, this list of conditions and the following 10// disclaimer in the documentation and/or other materials provided 11// with the distribution. 12// * Neither the name of Google Inc. nor the names of its 13// contributors may be used to endorse or promote products derived 14// from this software without specific prior written permission. 15// 16// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 17// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 18// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 19// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 20// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 21// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 22// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 26// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 28function IsNull(x) { 29 if (x == null) return true; else return false; 30} 31 32assertTrue(IsNull(null), "null == null"); 33assertTrue(IsNull(void 0), "void 0 == null"); 34assertFalse(IsNull(42), "42 != null"); 35 36 37function IsNullStrict(x) { 38 if (x === null) return true; else return false; 39} 40 41assertTrue(IsNullStrict(null), "null === null"); 42assertFalse(IsNullStrict(void 0), "void 0 != null"); 43assertFalse(IsNullStrict(87), "87 !== null"); 44 45 46function GimmeFalse(x) { 47 if ((x & 1) == null) return true; 48 if ((x | 3) === null) return true; 49 return false; 50} 51 52assertFalse(GimmeFalse(1), "GimmeFalse(1)"); 53assertFalse(GimmeFalse(null), "GimmeFalse(null)"); 54assertFalse(GimmeFalse({}), "GimmeFalse({})"); 55