ary-ptrn-elem-ary-elision-init.js (1582B)
1 // |reftest| async 2 // This file was procedurally generated from the following sources: 3 // - src/dstr-binding/ary-ptrn-elem-ary-elision-init.case 4 // - src/dstr-binding/default/async-gen-func-expr.template 5 /*--- 6 description: BindingElement with array binding pattern and initializer is used (async generator function expression) 7 esid: sec-asyncgenerator-definitions-evaluation 8 features: [generators, 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 BindingElement : BindingPatternInitializer opt 23 24 [...] 25 2. If iteratorRecord.[[done]] is true, let v be undefined. 26 3. If Initializer is present and v is undefined, then 27 a. Let defaultValue be the result of evaluating Initializer. 28 b. Let v be ? GetValue(defaultValue). 29 4. Return the result of performing BindingInitialization of BindingPattern 30 with v and environment as the arguments. 31 32 ---*/ 33 var first = 0; 34 var second = 0; 35 function* g() { 36 first += 1; 37 yield; 38 second += 1; 39 }; 40 41 42 var callCount = 0; 43 var f; 44 f = async function*([[,] = g()]) { 45 assert.sameValue(first, 1); 46 assert.sameValue(second, 0); 47 callCount = callCount + 1; 48 }; 49 50 f([]).next().then(() => { 51 assert.sameValue(callCount, 1, 'invoked exactly once'); 52 }).then($DONE, $DONE);