$jsonpCallbacksProvider = /** @this */ function() {
  this.$get = function() {
    var callbacks = angular.callbacks;
    var callbackMap = {};

    function createCallback(callbackId) {
      var callback = function(data) {
        callback.data = data;
        callback.called = true;
      };
      callback.id = callbackId;
      return callback;
    }

    return {
      /**
       * @ngdoc method
       * @name $jsonpCallbacks#createCallback
       * @param {string} url the url of the JSONP request
       * @returns {string} the callback path to send to the server as part of the JSONP request
       * @description
       * {@link $httpBackend} calls this method to create a callback and get hold of the path to the callback
       * to pass to the server, which will be used to call the callback with its payload in the JSONP response.
       */
      createCallback: function(url) {
        var callbackId = '_' + (callbacks.$$counter++).toString(36);
        var callbackPath = 'angular.callbacks.' + callbackId;
        var callback = createCallback(callbackId);
        callbackMap[callbackPath] = callbacks[callbackId] = callback;
        return callbackPath;
      },
      /**
       * @ngdoc method
       * @name $jsonpCallbacks#wasCalled
       * @param {string} callbackPath the path to the callback that was sent in the JSONP request
       * @returns {boolean} whether the callback has been called, as a result of the JSONP response
       * @description
       * {@link $httpBackend} calls this method to find out whether the JSONP response actually called the
       * callback that was passed in the request.
       */
      wasCalled: function(callbackPath) {
        return callbackMap[callbackPath].called;
      },
      /**
       * @ngdoc method
       * @name $jsonpCallbacks#getResponse
       * @param {string} callbackPath the path to the callback that was sent in the JSONP request
       * @returns {*} the data received from the response via the registered callback
       * @description
       * {@link $httpBackend} calls this method to get hold of the data that was provided to the callback
       * in the JSONP response.
       */
      getResponse: function(callbackPath) {
        return callbackMap[callbackPath].data;
      },
      /**
       * @ngdoc method
       * @name $jsonpCallbacks#removeCallback
       * @param {string} callbackPath the path to the callback that was sent in the JSONP request
       * @description
       * {@link $httpBackend} calls this method to remove the callback after the JSONP request has
       * completed or timed-out.
       */
      removeCallback: function(callbackPath) {
        var callback = callbackMap[callbackPath];
        delete callbacks[callback.id];
        delete callbackMap[callbackPath];
      }
    };
  };
}
@ngdoc service
@name $jsonpCallbacks
@requires $window
@description
This service handles the lifecycle of callbacks to handle JSONP requests.
Override this service if you wish to customise where the callbacks are stored and
how they vary compared to the requested url.