JSTests/test262/test/language/statements/for-await-of/async-gen-dstr-let-async-ary-ptrn-elision.js

// This file was procedurally generated from the following sources:
// - src/dstr-binding-for-await/ary-ptrn-elision.case
// - src/dstr-binding-for-await/default/for-await-of-async-gen-let-async.template
/*---
description: Elision advances iterator (for-await-of statement)
esid: sec-for-in-and-for-of-statements-runtime-semantics-labelledevaluation
features: [generators, destructuring-binding, async-iteration]
flags: [generated, async]
info: |
    IterationStatement :
        for await ( ForDeclaration of AssignmentExpression ) Statement

    [...]
    2. Return ? ForIn/OfBodyEvaluation(ForDeclaration, Statement, keyResult,
        lexicalBinding, labelSet, async).

    13.7.5.13 Runtime Semantics: ForIn/OfBodyEvaluation

    [...]
    4. Let destructuring be IsDestructuring of lhs.
    [...]
    6. Repeat
       [...]
       j. If destructuring is false, then
          [...]
       k. Else
          i. If lhsKind is assignment, then
             [...]
          ii. Else if lhsKind is varBinding, then
              [...]
          iii. Else,
               1. Assert: lhsKind is lexicalBinding.
               2. Assert: lhs is a ForDeclaration.
               3. Let status be the result of performing BindingInitialization
                  for lhs passing nextValue and iterationEnv as 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 iterCount = 0;
var asyncIter = (async function*() {
  yield* [g()];
})();

async function *fn() {
  for await (let [,] of asyncIter) {
    assert.sameValue(first, 1);
    assert.sameValue(second, 0);

    iterCount += 1;
  }
}

fn().next()
  .then(() => assert.sameValue(iterCount, 1, 'iteration occurred as expected'), $DONE)
  .then($DONE, $DONE);