| // This file was procedurally generated from the following sources: |
| // - src/dstr-binding/ary-ptrn-elem-id-init-undef.case |
| // - src/dstr-binding/default/gen-func-expr-dflt.template |
| /*--- |
| description: Destructuring initializer with an undefined value (generator function expression (default parameter)) |
| esid: sec-generator-function-definitions-runtime-semantics-evaluation |
| features: [generators, destructuring-binding, default-parameters] |
| flags: [generated] |
| info: | |
| GeneratorExpression : function * ( FormalParameters ) { GeneratorBody } |
| |
| [...] |
| 3. Let closure be GeneratorFunctionCreate(Normal, FormalParameters, |
| GeneratorBody, scope, strict). |
| [...] |
| |
| 9.2.1 [[Call]] ( thisArgument, argumentsList) |
| |
| [...] |
| 7. Let result be OrdinaryCallEvaluateBody(F, argumentsList). |
| [...] |
| |
| 9.2.1.3 OrdinaryCallEvaluateBody ( F, argumentsList ) |
| |
| 1. Let status be FunctionDeclarationInstantiation(F, argumentsList). |
| [...] |
| |
| 9.2.12 FunctionDeclarationInstantiation(func, argumentsList) |
| |
| [...] |
| 23. Let iteratorRecord be Record {[[iterator]]: |
| CreateListIterator(argumentsList), [[done]]: false}. |
| 24. If hasDuplicates is true, then |
| [...] |
| 25. Else, |
| b. Let formalStatus be IteratorBindingInitialization for formals with |
| iteratorRecord and env as arguments. |
| [...] |
| |
| 13.3.3.6 Runtime Semantics: IteratorBindingInitialization |
| |
| SingleNameBinding : BindingIdentifier Initializeropt |
| |
| [...] |
| 6. If Initializer is present and v is undefined, then |
| a. Let defaultValue be the result of evaluating Initializer. |
| b. Let v be GetValue(defaultValue). |
| [...] |
| 7. If environment is undefined, return PutValue(lhs, v). |
| 8. Return InitializeReferencedBinding(lhs, v). |
| ---*/ |
| |
| var callCount = 0; |
| var f; |
| f = function*([x = 23] = [undefined]) { |
| assert.sameValue(x, 23); |
| callCount = callCount + 1; |
| }; |
| |
| f().next(); |
| assert.sameValue(callCount, 1, 'generator function invoked exactly once'); |