script-decl-lex.js (1658B)
1 // Copyright (C) 2016 the V8 project authors. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 /*--- 4 esid: sec-globaldeclarationinstantiation 5 es6id: 15.1.8 6 description: Declaration of lexical bindings 7 info: | 8 [...] 9 16. For each element d in lexDeclarations do 10 a. NOTE Lexically declared names are only instantiated here but not 11 initialized. 12 b. For each element dn of the BoundNames of d do 13 i. If IsConstantDeclaration of d is true, then 14 1. Perform ? envRec.CreateImmutableBinding(dn, true). 15 ii. Else, 16 1. Perform ? envRec.CreateMutableBinding(dn, false). 17 [...] 18 ---*/ 19 20 // Extensibility of the global object should have no bearing on lexical 21 // declarations. 22 Object.preventExtensions(this); 23 24 $262.evalScript('let test262let = 1;'); 25 26 test262let = 2; 27 28 assert.sameValue(test262let, 2, '`let` binding is mutable'); 29 assert.sameValue( 30 this.hasOwnProperty('test262let'), 31 false, 32 'property not created on the global object (let)' 33 ); 34 35 $262.evalScript('const test262const = 3;'); 36 37 assert.throws(TypeError, function() { 38 test262const = 4; 39 }, '`const` binding is strictly immutable'); 40 assert.sameValue(test262const, 3, '`const` binding cannot be modified'); 41 assert.sameValue( 42 this.hasOwnProperty('test262const'), 43 false, 44 'property not created on the global object (const)' 45 ); 46 47 $262.evalScript('class test262class {}'); 48 49 test262class = 5; 50 51 assert.sameValue(test262class, 5, '`class` binding is mutable'); 52 assert.sameValue( 53 this.hasOwnProperty('test262class'), 54 false, 55 'property not created on the global object (class)' 56 ); 57 58 reportCompare(0, 0);