1// Copyright 2008 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// Flags: --legacy-const 29 30// const variables should be read-only 31const c = 42; 32c = 87; 33assertEquals(42, c); 34 35 36// const variables are not behaving like other JS variables when it comes 37// to scoping - in fact they behave more sanely. Inside a 'with' they do 38// not interfere with the 'with' scopes. 39 40(function () { 41 with ({ x: 42 }) { 42 const x = 7; 43 } 44 x = 5; 45 assertEquals(7, x); 46})(); 47 48 49// const variables may be declared but never initialized, in which case 50// their value is undefined. 51 52(function (sel) { 53 if (sel == 0) 54 with ({ x: 42 }) { 55 const x; 56 } 57 else 58 x = 3; 59 x = 5; 60 assertTrue(typeof x == 'undefined'); 61})(1); 62 63 64// const variables may be initialized to undefined. 65(function () { 66 with ({ x: 42 }) { 67 const x = undefined; 68 } 69 x = 5; 70 assertTrue(typeof x == 'undefined'); 71})(); 72 73 74// const variables may be accessed in inner scopes like any other variable. 75(function () { 76 function bar() { 77 assertEquals(7, x); 78 } 79 with ({ x: 42 }) { 80 const x = 7; 81 } 82 x = 5 83 bar(); 84})(); 85 86 87// const variables may be declared via 'eval' 88(function () { 89 with ({ x: 42 }) { 90 eval('const x = 7'); 91 } 92 x = 5; 93 assertEquals(7, x); 94})(); 95