Node.js - call async method without using promise third party library in nodejs

I am new to Node.js programming. I came to know about promise object. But one of my colleagues faced an interview question.

1. Without using any third party promise libraries which are available in npm(example Promise, bluebird), I need to implement a promise function which returns then() and catch() function like below.

   asyncPromise().then().catch()

For example:

function asyncFunction(cb){
    //-----------
    cb(err,data);
}

function asyncPromise(){
}

We need to Wrap a function around that function that it will make it behave as a promise. How can we achieve this with both of above functions, without using the third party libraries?

via Mohan Raja