array-elem-iter-nrml-close-null.js (2183B)
1 // This file was procedurally generated from the following sources: 2 // - src/dstr-assignment/array-elem-iter-nrml-close-null.case 3 // - src/dstr-assignment/error/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, 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 _; 45 var iterable = {}; 46 var nextCount = 0; 47 var iterator = { 48 next: function() { 49 nextCount += 1; 50 // Set an upper-bound to limit unnecessary iteration in non-conformant 51 // implementations 52 return { done: nextCount > 10 }; 53 }, 54 return: function() { 55 return null; 56 } 57 }; 58 iterable[Symbol.iterator] = function() { 59 return iterator; 60 }; 61 62 var counter = 0; 63 64 assert.throws(TypeError, function() { 65 for ([ _ ] of [iterable]) { 66 counter += 1; 67 } 68 counter += 1; 69 }); 70 71 assert.sameValue(counter, 0); 72 73 reportCompare(0, 0);