debounce.js

'use strict';

angular.module('debounce').factory('debounce', function($timeout, $q) {
  return function(func, wait, immediate) {
    var timeout;
    var deferred = $q.defer();
    return function() {
      var context = this, args = arguments;
      var later = function() {
        timeout = null;
        if(!immediate) {
          deferred.resolve(func.apply(context, args));
          deferred = $q.defer();
        }
      };
      var callNow = immediate && !timeout;
      if ( timeout ) {
        $timeout.cancel(timeout);
      }
      timeout = $timeout(later, wait);
      if (callNow) {
        deferred.resolve(func.apply(context,args));
        deferred = $q.defer();
      }
      return deferred.promise;
    };
  };
});