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 28 function IsNull(x) { 29 if (x == null) return true; else return false; 30 } 31 32 assertTrue(IsNull(null), "null == null"); 33 assertTrue(IsNull(void 0), "void 0 == null"); 34 assertFalse(IsNull(42), "42 != null"); 35 36 37 function IsNullStrict(x) { 38 if (x === null) return true; else return false; 39 } 40 41 assertTrue(IsNullStrict(null), "null === null"); 42 assertFalse(IsNullStrict(void 0), "void 0 != null"); 43 assertFalse(IsNullStrict(87), "87 !== null"); 44 45 46 function GimmeFalse(x) { 47 if ((x & 1) == null) return true; 48 if ((x | 3) === null) return true; 49 return false; 50 } 51 52 assertFalse(GimmeFalse(1), "GimmeFalse(1)"); 53 assertFalse(GimmeFalse(null), "GimmeFalse(null)"); 54 assertFalse(GimmeFalse({}), "GimmeFalse({})"); 55
