AngularJS - wait for multiple resource queries to complete

The solution from Ben Lesh is the best but it's not complete. If you need to handle error conditions--and, yes, you do--then you must use the catch method on the promise API like this:

$q.all([
   doQuery('billing'),
   doQuery('shipping')
]).then(function(data) {
   var billingAccounts = data[0];
   var shippingAccounts = data[1];

   //TODO: something...

}).catch(function(data) {

   //TODO: handle the error conditions...

}).finally(function () {

  //TODO: do final clean up work, etc...

});

If you don't define catch and all of your promises fail, then the then method won't ever execute and thus will probably leave your interface in a bad state.

You'll want to use promises and $q.all().

Basically, you can use it to wrap all of your $resource or $http calls because they return promises.

function doQuery(type) {
   var d = $q.defer();
   var result = Account.query({ type: type }, function() {
        d.resolve(result);
   });
   return d.promise;
}

$q.all([
   doQuery('billing'),
   doQuery('shipping')
]).then(function(data) {
   var billingAccounts = data[0];
   var shippingAccounts = data[1];

   //TODO: something...
});

I think a better solution is:

$q.all([
   Account.query({ type: 'billing' }).$promise,
   Account.query({ type: 'shipping' }).$promise
]).then(function(data) {
   var billingAccounts = data[0];
   var shippingAccounts = data[1];

   //TODO: something...
});