setting a class instance variable from a callback via this is undefined

Question

I have the following code. After call back is finished, I want to set the boolean to true but it fails with "undefined".

const processor = Processor.createInstance();

class Person {
    private status = {
        failed: true
      }

  processInfo(){

   processor.process(function(d){
       //do stuff now then set stays to false
      this.status.failed = false; //fails with "failed" of undefined.
    });

    }

 }

Attempted solutions:

1. create a function that sets status.failed to true then pass the function as a parameter to the processInfo() method and call it:

   function setStatus(status) { this.status.failed = status; }

   processInfo(statusUpdater){ processor.process(function(d){ //do stuff now then set stays to false statusUpdater(false); });

   }

still it fails with the same error message.

2nd: pass status object as a parameter to processInfo. It does work but not sure why or if it is the right way.