将Ajax回调函数值分配给javascript变量

Question

I have a function called getData which makes an ajax request. I want to use this ajax request result on my form submission for validation along with other validation. Since ajax is asynchronous i am calling a callback function inside my success function.

Now i want to assign the callback function value to a javascript variable for my form validation. I have tried using jquery validation submit handler method but that doesnt work either. My callback function is returning the desired output, but when i try to console.log the variable i have assigned it too, it returns undefined

Here is my code

function getData(cb){
    $.ajax({
             url:'/stops/reason_valid',
              method: 'get',
             dataType: "json",
             success: function(data)    {
               if(data.reason == '6'){
                   if(($('.search_of_item1').is(':checked')) || ($('.search_of_item2').is(':checked'))){
                      $(".searchValidError").hide();
                      cb(false);
                    }
                    else{
                         $(".searchValidError").show();
                         cb(true);
                    }
               }
            }
          })
  }

  $(".actionstaken_submit").click(function(e){

    var validationFailed = false;
    var searchValidation = getData(function(cb){
          alert(cb);
          return cb;
          });
    console.log(searchValidation);

    if($('.no_validation').is(":checked")){
      if($('.action_validation:checked').length > 1){
        $('.noneError').show();
        validationFailed = true;
      }
      else{
        $('.noneError').hide();
        validationFailed =  validationFailed || false;
      }
    }

    if (validationFailed || searchValidation) {
       e.preventDefault();
       return false;
    }
  });

Note: if i do alert(cb) display's the appropriate value but console.log(searchValidation) returns undefined

Answer 1

....Since ajax is asynchronous i am calling a callback function inside my success function.

Right. But there is an issue. You continue to fail when you write:

var searchValidation = getData(function(cb){
      alert(cb);
      return cb;
});
console.log(searchValidation);

This is like you are doing the same error: the function is asynchronous as the call. There is more than one approach to solve your issue. I suggest you to consider the jQuery event property isTrigger . When you rise an event with .trigger() the event object contains such a property.

Hence, you can change your code to:

$(".actionstaken_submit").click(function (e) {
            if (e.isTrigger !== undefined) { // <-- is event risen from .trigger() ?
                return;
            }
            e.preventDefault();

            var validationFailed = false;

            if ($('.no_validation').is(":checked")) {
                if ($('.action_validation:checked').length > 1) {
                    $('.noneError').show();
                    validationFailed = true;
                }
                else {
                    $('.noneError').hide();
                    validationFailed = validationFailed || false;
                }
            }

            getData(function (searchValidation) {
                console.log(searchValidation);
                if (!(validationFailed || searchValidation)) {
                    $(".actionstaken_submit").trigger('click'); // <-- raise the event
        }
    });
});

Another solution can be based on triggering the submit event:

$(".actionstaken_submit").closest('form').trigger('submit');

 function getData(cb) { cb($(':checkbox').prop('checked')); return; // for debug purposes.... $.ajax({ url: '1.json', method: 'get', dataType: "json", success: function (data) { if (data.reason == '6') { if (($('.search_of_item1').is(':checked')) || ($('.search_of_item2').is(':checked'))) { $(".searchValidError").hide(); cb(false); } else { $(".searchValidError").show(); cb(true); } } else { cb(false); // <------- added..... } } }) } $(".actionstaken_submit").click(function (e) { if (e.isTrigger !== undefined) { // <-- is event risen from .trigger() ? return; } e.preventDefault(); var validationFailed = false; if ($('.no_validation').is(":checked")) { if ($('.action_validation:checked').length > 1) { $('.noneError').show(); validationFailed = true; } else { $('.noneError').hide(); validationFailed = validationFailed || false; } } getData(function (searchValidation) { console.log(searchValidation); if (!(validationFailed || searchValidation)) { $(".actionstaken_submit").trigger('click'); // <-- raise the event } }); }); 

 <script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script> <form > <input type="checkbox"> searchValidation?<br/> <input type="submit" class="actionstaken_submit" value="Submit"> </form> 

Answer 2

Hi I change the code on the fly but what you have to do is run the validations of your click event inside a callback, or a deferred method as done or then.

Example:

function getData(){
   return $.ajax({
             url:'/stops/reason_valid',
              method: 'get',
             dataType: "json"
          })
  }

      function validate_submit(e){

  var validationFailed = false;
        var searchValidation = false;
     getData(searchValidation,validationFailed)
     .done((data)=>{


         console.log(data);
        if(data.reason == '6'){
      if(($('.search_of_item1').is(':checked')) || ($('.search_of_item2').is(':checked'))){
        $(".searchValidError").hide();
      }
      else{
        $(".searchValidError").show();
       searchValidation = true;
      }
    }
     }).always(()=>{
         console.log(searchValidation);
         if($('.no_validation').is(":checked")){
      if($('.action_validation:checked').length > 1){
        $('.noneError').show();
        validationFailed = true;
      }
      else{
        $('.noneError').hide();
        validationFailed =  validationFailed || false;
      }
    }

    if (validationFailed || searchValidation) {
       e.preventDefault();
       alert('oh shit here we go again');
       return false;
    }
     })
return false;
}

  $(".actionstaken_submit").click(function(e){
       validate_submit(e);
  });

Hope it helps =)