How to best organize translation strings in angular-translate?

Question

I am using angular-translate on a rather large Angular project. I am breaking the project into multiple modules to make it more manageable, but I am unable to break up my translation strings per module.

For example, I have modules A and B, where B is a submodule of A. There are strings that pertain to the HTML covered by module A, which are placed in '/json/localization/A/en.json'. Likewise, there are strings pertaining to B that I place in '/json/localization/B/en.json'. First I load B's en.json in module B using angular-translate's $translationProvider. Then I load module A's en.json, also using $translationProvider. The problem is that loading A's strings overrides B's strings and they are lost.

Using angular-translate, is there a way to load strings per module, without overriding, or does the parent module have to load all of the strings from a single en.json?

Here is an example (in coffeescript) of how I am loading the translation strings:

my_module.config(['$translateProvider', ($translateProvider) ->
  $translateProvider.useStaticFilesLoader
    prefix: '/json/localization/A/'
    suffix: '.json'

  $translateProvider.preferredLanguage 'en'
])

Answer 1

angular-translate supports async loading of partial language files. All partials are merged into one dictionary per language. The official documentation can be found here: http://angular-translate.github.io/docs/#/guide/12_asynchronous-loading

It supports applying a template for url templates that point to the modularised language files:

$translateProvider.useLoader('$translatePartialLoader', {  
  urlTemplate: '/i18n/{part}/{lang}.json'
});

From within your controllers, you can add language modules and refresh the data bindings like this:

angular.module('contact')
  .controller('ContactCtrl',
    function ($scope, $translatePartialLoader, $translate) {  
      $translatePartialLoader.addPart('contact');
      $translate.refresh();
    });

Of course, loading the partials can also be covered in a route's resolve phase

Alternatively, you can also look into building your own custom loader function. http://angular-translate.github.io/docs/#/guide/13_custom-loaders

This provides all the flexibility you need to combine required language modules in one shot. E.g. you could do something like this:

app.factory('customLoader', function ($http, $q) {
  // return loaderFn
  return function (options) {
    var deferred = $q.defer(); 
    var data = {
      'TEXT': 'Fooooo'
    };
    $http.get('nls/moduleA/en.json').success(function(moduleA){
      angular.extend(data, moduleA);
      $http.get('nls/moduleB/en.json').success(function(moduleB){
        angular.extend(data, moduleB);
        deferred.resolve(data);
      });
    });
    return deferred.promise;  
  };
});