AngularJS: How to implement Service

Here is the simple implementation for Calculator service. I have added two services in controller.js file from previous example and register it in app.js file.

controller.js

/* Define Service */

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

appService.service('mathService',function(){

    this.add = function(a,b){

        return a+b;

    };

    this.multiply = function(a,b){

        return a*b;

    };

});

appService.service('calculatorService', function(mathService){

    this.square = function(a){

        return mathService.multiply(a,a);

    };

});

app.js

var configModule = angular.module('configModule',[

    'ngRoute',

    'phoneDetailModule',

    'phoneListModule',

    'appFilter',

    'appService'

]);

HTML Code to invoke that service

Enter a number:

<input type="number" ng-model="number" />

<button ng-click="doSquare()">Square</button>