async-gen-decl-dstr-array-elem-nested-obj-yield-expr.js (1804B)
1 // |reftest| async 2 // This file was procedurally generated from the following sources: 3 // - src/dstr-assignment-for-await/array-elem-nested-obj-yield-expr.case 4 // - src/dstr-assignment-for-await/async-generator/async-gen-decl.template 5 /*--- 6 description: When a `yield` token appears within the Initializer of a nested destructuring assignment and within a generator function body, it behaves as a YieldExpression. (for-await-of statement in an async generator declaration) 7 esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation 8 features: [destructuring-binding, async-iteration] 9 flags: [generated, async] 10 info: | 11 IterationStatement : 12 for await ( LeftHandSideExpression of AssignmentExpression ) Statement 13 14 1. Let keyResult be the result of performing ? ForIn/OfHeadEvaluation(« », 15 AssignmentExpression, iterate). 16 2. Return ? ForIn/OfBodyEvaluation(LeftHandSideExpression, Statement, 17 keyResult, assignment, labelSet). 18 19 13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation 20 21 [...] 22 5. If destructuring is true and if lhsKind is assignment, then 23 a. Assert: lhs is a LeftHandSideExpression. 24 b. Let assignmentPattern be the parse of the source text corresponding to 25 lhs using AssignmentPattern as the goal symbol. 26 [...] 27 ---*/ 28 let x; 29 30 31 32 let iterCount = 0; 33 async function * fn() { 34 for await ([{ x = yield }] of [[{}]]) { 35 36 iterCount += 1; 37 } 38 } 39 40 let iter = fn(); 41 42 iter.next().then(result => { 43 assert.sameValue(result.value, undefined); 44 assert.sameValue(result.done, false); 45 assert.sameValue(x, undefined); 46 47 iter.next(4).then(result => { 48 assert.sameValue(result.value, undefined); 49 assert.sameValue(result.done, true); 50 assert.sameValue(x, 4); 51 }).then($DONE, $DONE); 52 }, $DONE).catch($DONE);