caching service in Angular

service.js

angular.module('app').factory('myService', function($q, $http){
  var data;
  var dataPromise;
  
  return {
    getData: getData
  }
  
  function getData(){
    //If the data is already here, return it in a resolved promise
    if(data != undefined) return $q.resolve(data);
    
    //If I am already in the process of getting the data from the server, return the same promise
    if(dataPromise != undefined) return dataPromise;
    
    //Otherwise, get the data, and return the promise to the caller
    dataPromise = $http.get('yourdataurl').then(function(result){
      data = result.data;
      dataPromise = undefined;
    })
    
    return dataPromise;
  }
});