Returning a $promise from two resource calls in AngularJS to delay route change

Question

Use Case

Using a route provider, returning a $promise in the resolve will avoid the data popping up after the UI has loaded. However, I'm having trouble processing two different resource calls and returning it as a single array.

Current Implementation

The current implementation works, but requires that the controller requires two resources.

var app = angular.module('app', []);

app.config(function($routeProvider) {
  $routeProvider
    .when('/resource/:id', {
      templateUrl: 'partials/resource.html',
      controller: ResourceController,
      resolve: {
        parentResource: function($route, SingleResource) {
          return SingleResource.get({ id: $route.current.params.id }).$promise;
        },
        childResources: function($route, ChildResource) {
          return ChildResource.get({ id: $route.current.params.id }).$promise;
        }
      }
  });
 });

However, what I'd like to do is provide ResourceController with a single array Resource that is an array composed of parentResource and childResource where item 0 in the array is the parentResource.

Idea

This is what I have in mind, but I don't know what to return in the resolve? If I return result, the route will change and pass an empty array.

var app = angular.module('app', []);

app.config(function($routeProvider) {
  $routeProvider
    .when('/resource/:id', {
      templateUrl: 'partials/resource.html',
      controller: ResourceController,
      resolve: {
        Resource: function($route, SingleResource) {
          var resources = [];
          SingleResource.get({ id: $route.current.params.id })
            .$promise.then(function(parent)
                             { resources.splice(0, 0, parent); })
                     .catch(function(error) { alert('error!'); })
          ChildResource.get({ id: $route.current.params.id })
            .$promise.then(function(children) 
                             { resources = resources .concat(children); })
                     .catch(function(error) { alert('error!'); })

          return ???? // Can I return a $promise here?
        }
      }
  });
});

Question

How can I get my ResourceController signature from The idea is then to get the controller to have this signature:

var ResourceController = function($scope, parentResource, childResources) { ... }

to

var ResourceController = function($scope, resources) { ... }

through returning $promise?

Answer 1

You can use $q.all to return an array of promises

var resources = [];

resources.push(SingleResource.get({ id: $route.current.params.id }).$promise);
resources.push(ChildResource.get({ id: $route.current.params.id }).$promise);

return $q.all(resources) // You return an array of promises

Answer 2

Try with like

 resolve: {
                parentResource: function($route, SingleResource) {
                  return SingleResource.get({ id: $route.current.params.id }).$promise;
                },
                childResources: function($route, ChildResource,  parentResource) {
                  return  (parentResource.length > 0) ? ChildResource.get({ id: $route.current.params.id }).$promise : [];
                }
              }

https://medium.com/opinionated-angularjs/a2fcbf874a1c