async-gen-decl-dstr-obj-prop-nested-obj-yield-expr.js (1821B)
1 // |reftest| async 2 // This file was procedurally generated from the following sources: 3 // - src/dstr-assignment-for-await/obj-prop-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 should behave 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: [generators, 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 = undefined; 29 30 31 let iterCount = 0; 32 async function * fn() { 33 for await ({ x: { x = yield } } of [{ x: {} }]) { 34 35 iterCount += 1; 36 } 37 } 38 39 let iter = fn(); 40 41 iter.next().then(result => { 42 assert.sameValue(result.value, undefined); 43 assert.sameValue(result.done, false); 44 assert.sameValue(x, undefined); 45 46 iter.next(4).then(result => { 47 assert.sameValue(result.value, undefined); 48 assert.sameValue(result.done, true); 49 assert.sameValue(x, 4); 50 }).then($DONE, $DONE); 51 });