How to create filter in Angularjs?

Question

I have this collection of courses:

 [{ id: 1, courseId: 2, text: \'John\' },
  { id: 2, courseId: 2, text: \'Willi\' },
  { id: 3, courseId: 2, text: \'Inga\' },         


        

Answer 1

I have created a filter in angularJs project.

in my angular app name is angularApp.

var app = angular.module('angularApp', []); // This is your main angular app.

Now you want to create a filter for decode url.

app.filter('decodeURL', function() {
    return function(text) {
        if(text) {
            return text.split(' ').join('-').toLowerCase().replace(/[^a-z0-9]+/g, '-');
        }
    }
});

The above code is to create a filter to decode url. And my filter name is 'decodeURL' . we will use decodeURL as a filter in my code like if your URL is-

http://www.example.com/test1 test2 tes3

then filter make the URL like this-

http://www.example.com/test1-test2-tes3

How to use this filter in the html-

<a ui-sref="{{business.category[0].categoryName.toLowerCase()}}Detail({id:business.id,title:(business.title | decodeURL)})"></a>

// The above is for state routing in angularjs.

<a href="/coupon/{{coupon.id}}/{{coupon.title | decodeURL}}"
                                       class="btn btn-warning show-btnhome show-button-margin">Show</a>

//The above code for URL redirecting.

Answer 2

You could create your custom filter so that can provide you the filtered values, filter should take array of element to be filter array.

Markup

ng-repeat="course in courses| customFilter: [{"id": 3},{"id": 2},{"id": 1}]""

Filter

app.filter('customFilter', function(){
  return function(array, filterArray){
     var ids = [];
     angular.forEach(filterArray, function(val, index) {
        ids.push(val.id);
     }
     return array.filter(function(value){
        return ids.indexOf(value.id) !== -1;
     });
  }
})