tor-browser

The Tor Browser
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short-circuit-number-symbol.js (2076B)

      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 (Symbol)
      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 var s = Symbol();
     39 
     40 x = undefined;
     41 x = s ?? 1;
     42 assert.sameValue(x, s, 's ?? null');
     43 
     44 x = undefined;
     45 x = s ?? null;
     46 assert.sameValue(x, s, 's ?? null');
     47 
     48 x = undefined;
     49 x = s ?? undefined;
     50 assert.sameValue(x, s, 's ?? undefined');
     51 
     52 x = undefined;
     53 x = s ?? null ?? undefined;
     54 assert.sameValue(x, s, 's ?? null ?? undefined');
     55 
     56 x = undefined;
     57 x = s ?? undefined ?? null;
     58 assert.sameValue(x, s, 's ?? undefined ?? null');
     59 
     60 x = undefined;
     61 x = s ?? null ?? null;
     62 assert.sameValue(x, s, 's ?? null ?? null');
     63 
     64 x = undefined;
     65 x = s ?? undefined ?? undefined;
     66 assert.sameValue(x, s, 's ?? null ?? null');
     67 
     68 x = undefined;
     69 x = null ?? s ?? null;
     70 assert.sameValue(x, s, 'null ?? s ?? null');
     71 
     72 x = undefined;
     73 x = null ?? s ?? undefined;
     74 assert.sameValue(x, s, 'null ?? s ?? undefined');
     75 
     76 x = undefined;
     77 x = undefined ?? s ?? null;
     78 assert.sameValue(x, s, 'undefined ?? s ?? null');
     79 
     80 x = undefined;
     81 x = undefined ?? s ?? undefined;
     82 assert.sameValue(x, s, 'undefined ?? s ?? undefined');
     83 
     84 reportCompare(0, 0);