覆盖getJSON并获取jQuery Promise（完成/失败）

Question

I have to override jQuery's getJSON function and am wondering if there is a way to get promise functions (done/fail) inside the override function. I would think that the functions are stored somewhere. Here is the start of the code:

(function ($) {
    $.getJSON = function (url, data, callback) {
       this.done = function(){};
       this.fail = function(){};
       var newDoneFtn = function(response) {
          var newData = JSON.parse(response.data);
          //call done function here with newData variable
       }
       var newFailFtn = function() {
          //call fail function here
       }
       newFunction(url, data, newDoneFtn, newFailFtn);
    };
})(jQuery);

$.getJSON(someURL, {
   id: 1
}).done(function(data) {
   console.log(data);
}).fail(function() {
   console.log('failed');
});

Where I am stuck is trying to get the done and failed functions on the getJSON call to be used with the newFunction. Please note that I cannot change newFunction.

Answer 1

You should create a new Deferred object using $.Deferred() .

You can then call / pass its resolve() and reject() functions to resolve or fail its promise.

Answer 2

As SLaks already answered; you can return a $.Deferred :

function getJson(){
  var deferred = $.Deferred();
  try{
    someCallbackApi(
      param
      ,function(response){
        response.error
          ? deferred.reject(response.error)
          : deferred.resolve(JSON.parse(response.data))
      }
    );
  }catch(e){
    deferred.reject(e);
  }
  return deferred.promise();
}