tor-browser

The Tor Browser
git clone https://git.dasho.dev/tor-browser.git
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iteration-statement-for.js (1028B)

      1 // Copyright 2019 Google, LLC.  All rights reserved.
      2 // This code is governed by the BSD license found in the LICENSE file.
      3 /*---
      4 esid: prod-OptionalExpression
      5 description: >
      6  optional chain in init/test/update of for statement
      7 info: |
      8  IterationStatement
      9    for (Expression; Expression; Expression) Statement
     10 features: [optional-chaining]
     11 ---*/
     12 
     13 // OptionalExpression in test.
     14 let count;
     15 const obj = {a: true};
     16 for (count = 0; obj?.a; count++) {
     17  if (count > 0) break;
     18 }
     19 assert.sameValue(count, 1);
     20 
     21 // OptionalExpression in init/test/update.
     22 let count2 = 0;
     23 const obj2 = undefined;
     24 
     25 for (obj?.a; obj2?.a; obj?.a) { count2++; }
     26 assert.sameValue(count2, 0);
     27 
     28 for (obj?.a; undefined?.a; obj?.a) { count2++; }
     29 assert.sameValue(count2, 0);
     30 
     31 // Short-circuiting
     32 let touched = 0;
     33 const obj3 = {
     34  get a() {
     35    count++;
     36    return undefined; // explicit for clarity
     37  }
     38 };
     39 for (count = 0; true; obj3?.a?.[touched++]) {
     40  if (count > 0) { break; }
     41 }
     42 assert.sameValue(count, 1);
     43 assert.sameValue(touched, 0);
     44 
     45 reportCompare(0, 0);