test262/test/language/statements/async-generator/dstr-dflt-ary-ptrn-rest-ary-elision.js

// This file was procedurally generated from the following sources:
// - src/dstr-binding/ary-ptrn-rest-ary-elision.case
// - src/dstr-binding/default/async-gen-func-decl-dflt.template
/*---
description: Rest element containing an elision (async generator function declaration (default parameter))
esid: sec-asyncgenerator-definitions-instantiatefunctionobject
features: [generators, 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

    BindingRestElement : ... BindingPattern

    1. Let A be ArrayCreate(0).
    [...]
    3. Repeat
       [...]
       b. If iteratorRecord.[[done]] is true, then
          i. Return the result of performing BindingInitialization of
             BindingPattern with A and environment as the arguments.
       [...]

    13.3.3.6 Runtime Semantics: IteratorBindingInitialization

    ArrayBindingPattern : [ Elision ]

    1. Return the result of performing
       IteratorDestructuringAssignmentEvaluation of Elision with iteratorRecord
       as the argument.

    12.14.5.3 Runtime Semantics: IteratorDestructuringAssignmentEvaluation

    Elision : ,

    1. If iteratorRecord.[[done]] is false, then
       a. Let next be IteratorStep(iteratorRecord.[[iterator]]).
       b. If next is an abrupt completion, set iteratorRecord.[[done]] to true.
       c. ReturnIfAbrupt(next).
       d. If next is false, set iteratorRecord.[[done]] to true.
    2. Return NormalCompletion(empty).

---*/
var first = 0;
var second = 0;
function* g() {
  first += 1;
  yield;
  second += 1;
};


var callCount = 0;
async function* f([...[,]] = g()) {
  assert.sameValue(first, 1);
  assert.sameValue(second, 1);
  callCount = callCount + 1;
};
f().next().then(() => {
    assert.sameValue(callCount, 1, 'invoked exactly once');
}).then($DONE, $DONE);