ary-ptrn-elem-id-init-skipped.js (1527B)
1 // |reftest| async 2 // This file was procedurally generated from the following sources: 3 // - src/dstr-binding/ary-ptrn-elem-id-init-skipped.case 4 // - src/dstr-binding/default/async-gen-func-expr.template 5 /*--- 6 description: Destructuring initializer is not evaluated when value is not `undefined` (async generator function expression) 7 esid: sec-asyncgenerator-definitions-evaluation 8 features: [async-iteration] 9 flags: [generated, async] 10 info: | 11 AsyncGeneratorExpression : async [no LineTerminator here] function * ( FormalParameters ) { 12 AsyncGeneratorBody } 13 14 [...] 15 3. Let closure be ! AsyncGeneratorFunctionCreate(Normal, FormalParameters, 16 AsyncGeneratorBody, scope, strict). 17 [...] 18 19 20 13.3.3.6 Runtime Semantics: IteratorBindingInitialization 21 22 SingleNameBinding : BindingIdentifier Initializeropt 23 24 [...] 25 6. If Initializer is present and v is undefined, then 26 [...] 27 7. If environment is undefined, return PutValue(lhs, v). 28 8. Return InitializeReferencedBinding(lhs, v). 29 ---*/ 30 var initCount = 0; 31 function counter() { 32 initCount += 1; 33 } 34 35 36 var callCount = 0; 37 var f; 38 f = async function*([w = counter(), x = counter(), y = counter(), z = counter()]) { 39 assert.sameValue(w, null); 40 assert.sameValue(x, 0); 41 assert.sameValue(y, false); 42 assert.sameValue(z, ''); 43 assert.sameValue(initCount, 0); 44 callCount = callCount + 1; 45 }; 46 47 f([null, 0, false, '']).next().then(() => { 48 assert.sameValue(callCount, 1, 'invoked exactly once'); 49 }).then($DONE, $DONE);