tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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short-circuit-number-0.js (2050B)

      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    Short circuit if the CoalesceExpressionHead is not undefined or null (0)
      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 = 0 ?? 1;
     41 assert.sameValue(x, 0, '0 ?? 1');
     42 
     43 x = undefined;
     44 x = 0 ?? null;
     45 assert.sameValue(x, 0, '0 ?? null');
     46 
     47 x = undefined;
     48 x = 0 ?? undefined;
     49 assert.sameValue(x, 0, '0 ?? undefined');
     50 
     51 x = undefined;
     52 x = 0 ?? null ?? undefined;
     53 assert.sameValue(x, 0, '0 ?? null ?? undefined');
     54 
     55 x = undefined;
     56 x = 0 ?? undefined ?? null;
     57 assert.sameValue(x, 0, '0 ?? undefined ?? null');
     58 
     59 x = undefined;
     60 x = 0 ?? null ?? null;
     61 assert.sameValue(x, 0, '0 ?? null ?? null');
     62 
     63 x = undefined;
     64 x = 0 ?? undefined ?? undefined;
     65 assert.sameValue(x, 0, '0 ?? null ?? null');
     66 
     67 x = undefined;
     68 x = null ?? 0 ?? null;
     69 assert.sameValue(x, 0, 'null ?? 0 ?? null');
     70 
     71 x = undefined;
     72 x = null ?? 0 ?? undefined;
     73 assert.sameValue(x, 0, 'null ?? 0 ?? undefined');
     74 
     75 x = undefined;
     76 x = undefined ?? 0 ?? null;
     77 assert.sameValue(x, 0, 'undefined ?? 0 ?? null');
     78 
     79 x = undefined;
     80 x = undefined ?? 0 ?? undefined;
     81 assert.sameValue(x, 0, 'undefined ?? 0 ?? undefined');
     82 
     83 reportCompare(0, 0);