title: How to call other functions of same services in ionic (angular.js)
body: <p>I am working on a mobile app using ionic framework. I have created a common Utility services like this</p>
  
  <pre><code> .service('CommonUtilityService', function($q) {
          return {
              parseJsonDate:function(jsonDate){
                  var offset = new Date().getTimezoneOffset() * 60000;
                  var parts = /\/Date\((-?\d+)([+-]\d{2})?(\d{2})?.*/.exec(jsonDate);
  
                  if (parts[2] == undefined)
                      parts[2] = 0;
  
                  if (parts[3] == undefined)
                      parts[3] = 0;
  
                  return new Date(+parts[1] + offset + parts[2]*3600000 + parts[3]*60000);
              },
              daysBetween:function(date1String, date2String){
                  var ONE_DAY = 1000 * 60 * 60 * 24;
                  var ONE_MINUTE = 1000 * 60;
  
                  var d1 = new Date(date1String);
                  var d2 = new Date(date2String);
                  var d1_ms = d1.getTime() - d1.getTimezoneOffset() * ONE_MINUTE;
                  var d2_ms = d2.getTime() - d2.getTimezoneOffset() * ONE_MINUTE;
  
                  return Math.floor(d1_ms - d2_ms/ONE_DAY);
              },
              getNumberOfDays:function(jsonDate){
                 // var date = parseJsonDate(jsonDate);
                  var date = new Date();
                  var today = new Date();
                  return this.daysBetween(today,date);
              }
          }
      })
  </code></pre>
  
  <p>When I am trying to call daysBetween function inside getNumberOfDays function it is giving error </p>
  
  <pre><code>this.daysBetween is not a function
  </code></pre>
  
  <p>Can anyone tell me how can I call daysBetween function inside getNumberOfDays function.</p>