Is there a way in AngularJS to define constants with other constants?

As long as you don't need access to your constant in providers, this should work fine:

.constant('HOST', 'localhost')
.factory('URL', function(HOST) { return "http://" + HOST })

If you need access to you constants in providers, then I guess you have to do some more work:

.constants('HOST', 'localhost')
.provider('DOMAIN', function(HOST) {
    var domain = "http://" + HOST;
    this.value = function() { return domain };
    this.$get = this.value;
 })
 .provider("anyOtherProvider", function(DOMAINPovider) {
     var domain = DOMAINProvider.value();
 };
 .factory("anyOtherService", function(DOMAIN) {
 })

The AngularJS way to define dependencies between Controllers, Services and others is by dependency injection (DI). So if you have a controller A that depends on a service B you would have to create it like this:

var myApp = angular.module("exampleApp",[]);

myApp.controller("aCtrl", function(serviceB){
    // Controller functionally here
});

See, AngularJS will check the serviceB dependency and look for the service you created with that name. If you don't create one you will get an error.

So, if you want to create a constant A that depends on constant B, you would need to tell angular that A depends on B. But a constant can't have a dependency. A constant can return a function, but the DI won't work for the constant. Check this Fiddle so you can see for which methods DI work for.

So answering your question, you can't define a constant with other constants.

But you can do this:

angular.module('projectApp', [])
  .constant('domain', 'http://somedomain.com')
  .constant('api', '/some/api/info')
  .service('urls', function(domain, api) {this.apiUrl = domain + api;})

  .controller('mainCtrl',function($scope,urls) {

      $scope.url = urls.apiUrl;

  });

Check this fiddle to see it working:

If you want to understand more about DI, check out this post.


I do that this way:

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

constants.factory("Independent", [function() {
   return {
      C1: 42
   }
}]);

constants.factory('Constants', ["Independent", function(I) {
   return {
      ANSWER_TO_LIFE: I.C1
   }
}]);

An easy way to do this is like this:

var myApp = angular.module("exampleApp",[]);

myApp.constant('RESOURCES', (function() {
  // Define your variable
  var resource = 'http://127.0.0.1:8008';
  // Use the variable in your constants
  return {
    USERS_DOMAIN: resource,
    USERS_API: resource + '/users',
    BASIC_INFO: resource + '/api/info'
  }
})());

And use the constants like this:

myApp.controller("ExampleCtrl", function(RESOURCES){
  $scope.domain = RESOURCES.USERS_DOMAIN;
});

Credits: link