tor-browser

The Tor Browser
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chainable-if-parenthesis-covered-logical-and.js (1458B)


      1 // Copyright (C) 2019 Leo Balter. All rights reserved.
      2 // This code is governed by the BSD license found in the LICENSE file.
      3 
      4 /*---
      5 description: >
      6    CoalesceExpression is chainable with the LogicalANDExpression is any is covered.
      7 esid: sec-conditional-operator
      8 info: |
      9    ConditionalExpression :
     10        ShortCircuitExpression
     11        ShortCircuitExpression ? AssignmentExpression : AssignmentExpression
     12 
     13    ShortCircuitExpression :
     14        LogicalORExpression
     15        CoalesceExpression
     16 
     17    CoalesceExpression :
     18        CoalesceExpressionHead ?? BitwiseORExpression
     19 
     20    CoalesceExpressionHead :
     21        CoalesceExpression
     22        BitwiseORExpression
     23 
     24    Runtime Semantics: Evaluation
     25 
     26    CoalesceExpression:CoalesceExpressionHead??BitwiseORExpression
     27 
     28    1. Let lref be the result of evaluating CoalesceExpressionHead.
     29    2. Let lval be ? GetValue(lref).
     30    3. If lval is undefined or null,
     31        a. Let rref be the result of evaluating BitwiseORExpression.
     32        b. Return ? GetValue(rref).
     33    4. Otherwise, return lval.
     34 features: [coalesce-expression]
     35 ---*/
     36 
     37 var x;
     38 
     39 x = undefined;
     40 x = (null ?? 41) && 42;
     41 assert.sameValue(x, 42, '(null ?? 41) && 42');
     42 
     43 x = undefined;
     44 x = null ?? (41 && 42);
     45 assert.sameValue(x, 42, 'null ?? (41 && 42)`');
     46 
     47 x = undefined;
     48 x = (41 && 42) ?? null;
     49 assert.sameValue(x, 42, '(41 && 42) ?? null');
     50 
     51 x = undefined;
     52 x = 41 && (null ?? 42);
     53 assert.sameValue(x, 42, '41 && (null ?? 42)`');
     54 
     55 reportCompare(0, 0);