$q.all returns undefined for all values

Question

I'm trying to wait on 3 promises but $q.all appears to resolve them at once and returns undefined for each single value, I can't figure out why:

this.doWork = function() {
  var deferred = $q.defer();
  var a = get('a'),
    b = get('b'),
    c = get('c');
  $q.all([a.promise, b.promise, c.promise])
    .then(function(values) {
      deferred.resolve(new Test(values[0], values[1], values[2]));
    }, function(reason) {
      deferred.reject(reason);
    });
  return deferred.promise;
};

function get(param) {
  var deferred = $q.defer();
  $timeout(function() {
    if (true) {
      deferred.resolve({
        value: param
      });
    } else {
      deferred.reject({
        message: "Really bad"
      });
    }
  }, 1000);
  return deferred.promise;
}

(in the actual code get() uses $http instead of $timeout , of course). Here's a Plnkr with the code, can anybody please shed some light on what the issue is?

Answer 1

You should not be doing .promise on promise object returned by get method, because you had already returned promise form get method.

$q.all([a, b, c])

When you're doing a.promise , b.promise & c.promise they all becomes undefined & then $q.all array become $q.all([undefined, undefined, undefined]) passing them to $q.all will give undefined result.