how can I list available filters

Question

I have a scenario where I want the user to be able to select which filter to apply. I do not want to maintain a separate list of filters in the html. So considering the following code where I am trying to access the names of the registered filters. (I am an AngularJS newbie so apologies if this is obvious)

angular.module('app.filters', []);

angular.module('app.filters').filter('filter1', function() {/* filter code */});

angular.module('app.filters').filter('filter2', function() {/* another filter code */});

angular.module('app', ['app.filters']);

angular.module('app').controller('MainCtrl', function ($scope, $filter) {

    /* How do I list filter1 and filter2 in here so that they can be output
       in a template? The below means the filter names are recorded twice */

    $scope.availableFilters = ['filter1', 'filter2']
});

Answer 1

I guess there is no build in way of doing this. But you can get this information if you are hooking in the $filterProvider :

.config(function($filterProvider, $provide) {
    // keep the original register fucntion
    var registerFn = $filterProvider.register;
    // array with all filters
    var allFilters = [];

    // replace the register function with our own implementation
    $filterProvider.register = function(name, fn){
        // save the name in the array
        allFilters.push(name);
        // call the original function
        registerFn(name, fn);
    }

    // register a value to retrieve the filters
    $provide.value('filters', allFilters);

}) 

The filters value may now be used in your controller by injecting it:

.controller('MainCtrl', function(filters){
   // outputs an array with all known filters
   console.log(filters);
})