Javascript class variable becomes undefined with setTimeout loop despite declaring context

Question

The variable amountCompleted is set in a class because it became undefined when it was a global variable as well as when being passed into the function

amountCompleted becomes undefined after the recursive function auxReportProgress is called

How do I keep the context of amountCompleted with the following setTimeout loop?

function progressReport(importCount, progressID){
    this.amountCompleted = 0;
    this.importCount = importCount;
    this.progressID = progressID;
}

progressReport.prototype.auxReportProgress = function() {
    var self = this;

   if (self.amountCompleted < this.importCount) {
       var newAmount = reportProgress(this.progressID); 
           // make ajax call to get progress info

       if (newAmount){
       self.amountCompleted += newAmount;

           // indicate new amount
       }

       setTimeout(function() {self.auxReportProgress();}, 3000);

   }

}


    function reportProgress(progressID){    
        jQuery.ajax({method:'post',url:"{{=URL(r=request,f='call', args=       
        ['json','reportProgress'])}}",
                     data:{'progressID':progressID},
                     success: function(anyNewFiles){
                                    var newCompleted = 

         anyNewFiles['newCompleted'];
                                    return newCompleted.length;


                              }
         });
    }    

var progReport = new progressReport(importCount, progressID);
progReport.auxReportProgress();

Let me know if more info is needed. Any help is appreciated.

Thanks,

PV

What does `reportProgress` do (and return)? How do you know that `amountCompleted` is undefined? Please provide a complete example! — Felix Kling, Sep 05 '15 at 15:46
`WebWorker`s are great for communicating to and from a new thread, as may be the case in a progress reporter. https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Using_web_workers — ne1410s, Sep 05 '15 at 16:10
@Sherali -- importCount is declared in a separate ajax call that retrieves data just uploaded. — Phillip, Sep 06 '15 at 13:15
@Felix -- amountCompleted shows to be NaN in the console after the first call to reportProgress is made. — Phillip, Sep 06 '15 at 13:18
@Daniel -- It takes some time to process the data. newAmount is just to indicate whether to update a displayed flash response — Phillip, Sep 06 '15 at 13:23
`var newAmount = reportProgress(this.progressID);` is the problem - you cannot return the result synchronously from an ajax call, so `newAmout` is undefined here. The issue has nothing to do with your class code. — Bergi, Sep 06 '15 at 13:39

Javascript class variable becomes undefined with setTimeout loop despite declaring context

0 Answers0