async-gen-dstr-const-async-ary-ptrn-elem-id-init-undef.js (2142B)
1 // |reftest| async 2 // This file was procedurally generated from the following sources: 3 // - src/dstr-binding-for-await/ary-ptrn-elem-id-init-undef.case 4 // - src/dstr-binding-for-await/default/for-await-of-async-gen-const-async.template 5 /*--- 6 description: Destructuring initializer with an undefined value (for-await-of statement) 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 ( ForDeclaration of AssignmentExpression ) Statement 13 14 [...] 15 2. Return ? ForIn/OfBodyEvaluation(ForDeclaration, Statement, keyResult, 16 lexicalBinding, labelSet, async). 17 18 13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation 19 20 [...] 21 4. Let destructuring be IsDestructuring of lhs. 22 [...] 23 6. Repeat 24 [...] 25 j. If destructuring is false, then 26 [...] 27 k. Else 28 i. If lhsKind is assignment, then 29 [...] 30 ii. Else if lhsKind is varBinding, then 31 [...] 32 iii. Else, 33 1. Assert: lhsKind is lexicalBinding. 34 2. Assert: lhs is a ForDeclaration. 35 3. Let status be the result of performing BindingInitialization 36 for lhs passing nextValue and iterationEnv as arguments. 37 [...] 38 39 13.3.3.6 Runtime Semantics: IteratorBindingInitialization 40 41 SingleNameBinding : BindingIdentifier Initializer_opt 42 43 [...] 44 5. If Initializer is present and v is undefined, then 45 a. Let defaultValue be the result of evaluating Initializer. 46 b. Let v be GetValue(defaultValue). 47 [...] 48 6. If environment is undefined, return PutValue(lhs, v). 49 7. Return InitializeReferencedBinding(lhs, v). 50 ---*/ 51 52 var iterCount = 0; 53 var asyncIter = (async function*() { 54 yield* [[undefined]]; 55 })(); 56 57 async function *fn() { 58 for await (const [x = 23] of asyncIter) { 59 assert.sameValue(x, 23); 60 61 iterCount += 1; 62 } 63 } 64 65 fn().next() 66 .then(() => assert.sameValue(iterCount, 1, 'iteration occurred as expected'), $DONE) 67 .then($DONE, $DONE);