iterator-close-via-continue.js (1720B)
1 // Copyright (C) 2017 André Bargull. All rights reserved. 2 // This code is governed by the BSD license found in the LICENSE file. 3 4 /*--- 5 esid: sec-runtime-semantics-forin-div-ofbodyevaluation-lhs-stmt-iterator-lhskind-labelset 6 description: > 7 Iterators should be closed via their `return` method when iteration is 8 interrupted via a `continue` statement. 9 info: | 10 13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation ( lhs, stmt, iteratorRecord, iterationKind, lhsKind, labelSet ) 11 ... 12 5. Repeat, 13 ... 14 i. Let result be the result of evaluating stmt. 15 ... 16 k. If LoopContinues(result, labelSet) is false, then 17 i. If iterationKind is enumerate, then 18 ... 19 ii. Else, 20 1. Assert: iterationKind is iterate. 21 2. Return ? IteratorClose(iteratorRecord, UpdateEmpty(result, V)). 22 ... 23 24 features: [Symbol.iterator] 25 ---*/ 26 27 var startedCount = 0; 28 var returnCount = 0; 29 var iterationCount = 0; 30 var iterable = {}; 31 32 iterable[Symbol.iterator] = function() { 33 return { 34 next: function() { 35 startedCount += 1; 36 return { done: false, value: null }; 37 }, 38 return: function() { 39 returnCount += 1; 40 return {}; 41 } 42 }; 43 }; 44 45 L: do { 46 for (var x of iterable) { 47 assert.sameValue( 48 startedCount, 1, 'Value is retrieved' 49 ); 50 assert.sameValue( 51 returnCount, 0, 'Iterator is not closed' 52 ); 53 iterationCount += 1; 54 continue L; 55 } 56 } while (false); 57 58 assert.sameValue( 59 startedCount, 1, 'Iterator does not restart following interruption' 60 ); 61 assert.sameValue(iterationCount, 1, 'A single iteration occurs'); 62 assert.sameValue( 63 returnCount, 1, 'Iterator is closed after `continue` statement' 64 ); 65 66 reportCompare(0, 0);