// |reftest| async // This file was procedurally generated from the following sources: // - src/dstr-binding-for-await/ary-ptrn-elem-id-init-undef.case // - src/dstr-binding-for-await/default/for-await-of-async-gen-let.template /*--- description: Destructuring initializer with an undefined value (for-await-of statement) esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation features: [destructuring-binding, async-iteration] flags: [generated, async] info: | IterationStatement : for await ( ForDeclaration of AssignmentExpression ) Statement [...] 2. Return ? ForIn/OfBodyEvaluation(ForDeclaration, Statement, keyResult, lexicalBinding, labelSet, async). 13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation [...] 4. Let destructuring be IsDestructuring of lhs. [...] 6. Repeat [...] j. If destructuring is false, then [...] k. Else i. If lhsKind is assignment, then [...] ii. Else if lhsKind is varBinding, then [...] iii. Else, 1. Assert: lhsKind is lexicalBinding. 2. Assert: lhs is a ForDeclaration. 3. Let status be the result of performing BindingInitialization for lhs passing nextValue and iterationEnv as arguments. [...] 13.3.3.6 Runtime Semantics: IteratorBindingInitialization SingleNameBinding : BindingIdentifier Initializer_opt [...] 5. If Initializer is present and v is undefined, then a. Let defaultValue be the result of evaluating Initializer. b. Let v be GetValue(defaultValue). [...] 6. If environment is undefined, return PutValue(lhs, v). 7. Return InitializeReferencedBinding(lhs, v). ---*/ var iterCount = 0; async function *fn() { for await (let [x = 23] of [[undefined]]) { assert.sameValue(x, 23); iterCount += 1; } } fn().next() .then(() => assert.sameValue(iterCount, 1, 'iteration occurred as expected'), $DONE) .then($DONE, $DONE);