CODEWITHSUNDEEP
javascriptangularjspromise
alex
alex

Reputation: 7601

How to trigger a promise and then a second one with $q?

I'm using $q in a method to get an array of objects. I also have a method called getItems which makes use of this promise (all).

I use all a second time at the bottom, to do stuff with $scope.list. The code has to be wrapped inside all().then(function() { ... } so it only triggers when $scope.list ready.

var all = function() { return $q.all([service.getAllItems()]) }

var getItems = function() {
  all().then(function(value) {
     $scope.list = JSON.parse(value)
  }, function(reason) {
    $scope.result = reason
  })
}

getItems()

all().then(function() {
  // do stuff with $scope.list
}

This works...almost. Sometimes the first all finishes first and sometimes the second one. So sometimes $scope.list has the objects and sometimes it's empty.

How to create a new promise that only triggers when all fetches the array of objects?

Upvotes: 3

Views: 243

Answers (1)

Martijn Welker
Martijn Welker

Reputation: 5605

You can do it like so:

var all = function() { return $q.all([service.getAllItems()]) }

var getItems = function() {
  return all().then(function(value) {
     $scope.list = JSON.parse(value)
  }, function(reason) {
    $scope.result = reason
  });
}

getItems().then(function() {
  // do stuff with $scope.list
}

If you return a promise in a function you can chain a .then to it, so now your getItems will return the promise from all(), once this is fulfilled your code will continue

Upvotes: 7

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