How to return an array from jQuery ajax success fu

问题:

This question already has an answer here:

• How do I return the response from an asynchronous call? 33 answers

TheObject = {

    getArray: function(){
        var groups = new Array;
        $.ajax({
              type: "POST",
              url: "link.php",
              success: function (data){
                  var counter = 0;
                  $('g',data).each(function(){    
                      var group_name = $(this).find("name").text();
                      var group_id = $(this).find("id").text();
                      var group = {
                         id: group_id,
                         name: group_name
                      }
                      groups[counter] = group;
                      counter++;
                  });
                  return groups;
              }
         });
     }

}

And when I try to call this method:

var a = TheObject.getArray();
alert(a);

It returns 'undefined'. I cant figure out where is the problem. The array gets created inside the success function but I'am unable to return it properly. Thanks for your help!

回答1:

In your code, you are looking for groups using procedural coding after the ajax call was made. The main problem is that you are looking for groups before the ajax call is complete.

Another problem is that you are returning groups to the success() function, but the TheObject.getArray() function returns nothing.

So you need to bring in the callback into the ajax function like this:

TheObject = {
    getArray: function(callback) {
        var groups = new Array;
        $.ajax({
              type: "POST",
              url: "link.php",
              success: function (data){
                  var counter = 0;
                  $('g',data).each(function(){    
                      var group_name = $(this).find("name").text();
                      var group_id = $(this).find("id").text();
                      var group = {
                         id: group_id,
                         name: group_name
                      }
                      groups[counter] = group;
                      counter++;
                  });
                  callback.call(this,groups);
              }
         });
     }
}

TheObject.getArray(function(a) {
    // this code runs when the ajax call is complete
    alert(a);
});

回答2:

A very simple version of David's example.

TheObject = {
    getArray: function(callback) { 
        $.ajax({
              cache: true,
              type: "GET",
              url: "http://www.domain.com/core/domains.php",
              success: function (data){ 
                  callback.call(this,data);
              }
         });
     }
}

TheObject.getArray(function(data) {
    javascript: console.log(data);    
});

回答3:

Use push on the array. Also you want to create a type called Group and then create a new group in the loop and then push it into the array.