deps/v8/src/js/promise.js
function PromiseAll(iterable) {
  if (!IS_RECEIVER(this)) {
    throw MakeTypeError(kCalledOnNonObject, "Promise.all");
  }

  var deferred = NewPromiseCapability(this);
  var resolutions = new InternalArray();
  var count;

  function CreateResolveElementFunction(index, values, promiseCapability) {
    var alreadyCalled = false;
    return (x) => {
      if (alreadyCalled === true) return;
      alreadyCalled = true;
      values[index] = x;
      if (--count === 0) {
        var valuesArray = [];
        %MoveArrayContents(values, valuesArray);
        %_Call(promiseCapability.resolve, UNDEFINED, valuesArray);
      }
    };
  }

  try {
    var i = 0;
    count = 1;
    for (var value of iterable) {
      var nextPromise = this.resolve(value);
      ++count;
      nextPromise.then(
          CreateResolveElementFunction(i, resolutions, deferred),
          deferred.reject);
      SET_PRIVATE(deferred.reject, promiseCombinedDeferredSymbol, deferred);
      ++i;
    }

    // 6.d
    if (--count === 0) {
      var valuesArray = [];
      %MoveArrayContents(resolutions, valuesArray);
      %_Call(deferred.resolve, UNDEFINED, valuesArray);
    }

  } catch (e) {
    %_Call(deferred.reject, UNDEFINED, e);
  }
  return deferred.promise;
}
function PromiseAll(iterable) {
  if (!IS_RECEIVER(this)) {
    throw MakeTypeError(kCalledOnNonObject, "Promise.all");
  }

  var deferred = NewPromiseCapability(this);
  var resolutions = new InternalArray();
  var count;

  function CreateResolveElementFunction(index, values, promiseCapability) {
    var alreadyCalled = false;
    return (x) => {
      if (alreadyCalled === true) return;
      alreadyCalled = true;
      values[index] = x;
      if (--count === 0) {
        var valuesArray = [];
        %MoveArrayContents(values, valuesArray);
        %_Call(promiseCapability.resolve, UNDEFINED, valuesArray);
      }
    };
  }

  try {
    var i = 0;
    count = 1;
    for (var value of iterable) {
      var nextPromise = this.resolve(value);
      ++count;
      nextPromise.then(
          CreateResolveElementFunction(i, resolutions, deferred),
          deferred.reject);
      SET_PRIVATE(deferred.reject, promiseCombinedDeferredSymbol, deferred);
      ++i;
    }

    // 6.d
    if (--count === 0) {
      var valuesArray = [];
      %MoveArrayContents(resolutions, valuesArray);
      %_Call(deferred.resolve, UNDEFINED, valuesArray);
    }

  } catch (e) {
    %_Call(deferred.reject, UNDEFINED, e);
  }
  return deferred.promise;
}
ES#sec-promise.all Promise.all ( iterable )