http://www.codeproject.com/Tips/829025/How-to-Create-Custom-Filters-in-AngularJs
Introduction
Filter in Angular JS is a way that will help you to represent your data in View in a certain format. There are many inbuilt filters provided by Angular js that give us the way to format our data in View. With these inbuilt filters, we can format & show our data in various ways. Text can be shown in uppercase, lowercase. Date can be also represented in various formats. All we need to do it is add a "|" (pipe) after the data.
Example: {{ 'Hello World' | uppercase }}
We can also create custom filter to display our data in a particular way that we want.
Let's see how we can create a custom filter. I am going to implement a custom filter, which reverses the input entered in a text box.
How to Create Custom Filters
//Initialize your ng-app
var myapp = angular.module('MyApp', []);
//Create a Filter
myapp.filter("reversetext", function() {
//Defining the filter function
return function(input) {
var result = "";
input = input || "";
for (var i=0; i<input.length; i++) {
result = input.charAt(i) + result;
}
return result;
};
});
Now Use the Filter in your View with HTML
<body ng-app="MyApp">
<input type="text" ng-model="text" placeholder="Enter text"/>
<p>Filtered Reverse Input: {{ text | reversetext }}</p>
</body>