tor-browser

The Tor Browser
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array-elem-iter-rtrn-close-null.js (2445B)

      1 // This file was procedurally generated from the following sources:
      2 // - src/dstr-assignment/array-elem-iter-rtrn-close-null.case
      3 // - src/dstr-assignment/default/for-of.template
      4 /*---
      5 description: IteratorClose throws a TypeError when `return` returns a non-Object value (For..of statement)
      6 esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
      7 features: [Symbol.iterator, generators, destructuring-binding]
      8 flags: [generated]
      9 info: |
     10    IterationStatement :
     11      for ( LeftHandSideExpression of AssignmentExpression ) Statement
     12 
     13    1. Let keyResult be the result of performing ? ForIn/OfHeadEvaluation(« »,
     14       AssignmentExpression, iterate).
     15    2. Return ? ForIn/OfBodyEvaluation(LeftHandSideExpression, Statement,
     16       keyResult, assignment, labelSet).
     17 
     18    13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation
     19 
     20    [...]
     21    4. If destructuring is true and if lhsKind is assignment, then
     22       a. Assert: lhs is a LeftHandSideExpression.
     23       b. Let assignmentPattern be the parse of the source text corresponding to
     24          lhs using AssignmentPattern as the goal symbol.
     25    [...]
     26 
     27    ArrayAssignmentPattern : [ AssignmentElementList ]
     28 
     29    [...]
     30    5. If iteratorRecord.[[done]] is false, return IteratorClose(iterator,
     31       result).
     32    6. Return result.
     33 
     34    7.4.6 IteratorClose( iterator, completion )
     35 
     36    [...]
     37    6. Let innerResult be Call(return, iterator, « »).
     38    7. If completion.[[type]] is throw, return Completion(completion).
     39    8. If innerResult.[[type]] is throw, return Completion(innerResult).
     40    9. If Type(innerResult.[[value]]) is not Object, throw a TypeError
     41       exception.
     42 
     43 ---*/
     44 var nextCount = 0;
     45 var returnCount = 0;
     46 var unreachable = 0;
     47 var iterator = {
     48  next: function() {
     49    nextCount += 1;
     50    return {done: false, value: undefined};
     51  },
     52  return: function() {
     53    returnCount += 1;
     54    return null;
     55  }
     56 };
     57 var iterable = {};
     58 iterable[Symbol.iterator] = function() {
     59  return iterator;
     60 };
     61 function* g() {
     62 
     63 var counter = 0;
     64 
     65 for ([ {} = yield ] of [iterable]) {
     66  unreachable += 1;
     67  counter += 1;
     68 }
     69 
     70 assert.sameValue(counter, 1);
     71 
     72 }
     73 
     74 var iter = g();
     75 iter.next();
     76 
     77 assert.sameValue(nextCount, 1);
     78 assert.sameValue(returnCount, 0);
     79 assert.throws(TypeError, function() {
     80  iter.return();
     81 });
     82 assert.sameValue(nextCount, 1);
     83 assert.sameValue(returnCount, 1);
     84 assert.sameValue(unreachable, 0, 'Unreachable statement was not executed');
     85 
     86 reportCompare(0, 0);