dflt-ary-ptrn-elem-id-init-undef.js (1421B)
1 // |reftest| async 2 // This file was procedurally generated from the following sources: 3 // - src/dstr-binding/ary-ptrn-elem-id-init-undef.case 4 // - src/dstr-binding/default/async-gen-func-decl-dflt.template 5 /*--- 6 description: Destructuring initializer with an undefined value (async generator function declaration (default parameter)) 7 esid: sec-asyncgenerator-definitions-instantiatefunctionobject 8 features: [async-iteration] 9 flags: [generated, async] 10 info: | 11 AsyncGeneratorDeclaration : async [no LineTerminator here] function * BindingIdentifier 12 ( FormalParameters ) { AsyncGeneratorBody } 13 14 [...] 15 3. Let F be ! AsyncGeneratorFunctionCreate(Normal, FormalParameters, AsyncGeneratorBody, 16 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 a. Let defaultValue be the result of evaluating Initializer. 27 b. Let v be GetValue(defaultValue). 28 [...] 29 7. If environment is undefined, return PutValue(lhs, v). 30 8. Return InitializeReferencedBinding(lhs, v). 31 ---*/ 32 33 34 var callCount = 0; 35 async function* f([x = 23] = [undefined]) { 36 assert.sameValue(x, 23); 37 callCount = callCount + 1; 38 }; 39 f().next().then(() => { 40 assert.sameValue(callCount, 1, 'invoked exactly once'); 41 }).then($DONE, $DONE);