Return object from AJAX request

Question

User439975351 posted

HI guys,

I have a function that I want to pass back the response object but being async this passes back undefined. How can I achieve this and get the object back to the caller?

Thanks,

Jus

   var check = checkConstraints(reqData);

   if(check.IsValid == true){
      //Do this...
   }

   function checkConstraints(reqData){
          var request = $.ajax({
          type: "POST",
          url: urlPrefix + "/check-constraints",
          data: reqData,                      
          dataType: "json"
       });

       request.done(function (data) {

          return data; //returns undefined

       });
   }

Answer 1

User-474980206 posted

the function should return a promise:

   var check = checkConstraints(reqData).done(function(check) {
      if(check.IsValid == true){
         //Do this...
      }
   }

   function checkConstraints(reqData){
       return $.ajax({
          type: "POST",
          url: urlPrefix + "/check-constraints",
          data: reqData,                      
          dataType: "json"
       }).done(function(data) {
          // process data
          var check = data;
          return check;
       });
   }

if using modern javascript its:

   const check = await checkConstraints(reqData);
   if(check.IsValid == true){
         //Do this...
   }
   

   async function checkConstraints(reqData){
       const data = await $.ajax({
          type: "POST",
          url: urlPrefix + "/check-constraints",
          data: reqData,                      
          dataType: "json"
       });

       // process data
       let check = data;
       return check;
   }

Answer 2

User439975351 posted

Thanks bruce, I have opted for the second option here which works perfectly. 

All the best,

Jus