JSTests/test262/test/language/statements/async-generator/dstr/ary-ptrn-elem-id-init-skipped.js

// This file was procedurally generated from the following sources:
// - src/dstr-binding/ary-ptrn-elem-id-init-skipped.case
// - src/dstr-binding/default/async-gen-func-decl.template
/*---
description: Destructuring initializer is not evaluated when value is not `undefined` (async generator function declaration)
esid: sec-asyncgenerator-definitions-instantiatefunctionobject
features: [async-iteration]
flags: [generated, async]
info: |
    AsyncGeneratorDeclaration : async [no LineTerminator here] function * BindingIdentifier
        ( FormalParameters ) { AsyncGeneratorBody }

        [...]
        3. Let F be ! AsyncGeneratorFunctionCreate(Normal, FormalParameters, AsyncGeneratorBody,
            scope, strict).
        [...]


    13.3.3.6 Runtime Semantics: IteratorBindingInitialization

    SingleNameBinding : BindingIdentifier Initializeropt

    [...]
    6. If Initializer is present and v is undefined, then
       [...]
    7. If environment is undefined, return PutValue(lhs, v).
    8. Return InitializeReferencedBinding(lhs, v).
---*/
var initCount = 0;
function counter() {
  initCount += 1;
}


var callCount = 0;
async function* f([w = counter(), x = counter(), y = counter(), z = counter()]) {
  assert.sameValue(w, null);
  assert.sameValue(x, 0);
  assert.sameValue(y, false);
  assert.sameValue(z, '');
  assert.sameValue(initCount, 0);
  callCount = callCount + 1;
};
f([null, 0, false, '']).next().then(() => {
    assert.sameValue(callCount, 1, 'invoked exactly once');
}).then($DONE, $DONE);