How to spawn new process everytime I call a recursive function in Node.js

I am new to node.I am trying to create a recursive function say Merge Sort.I want to create a new process every time I call the function.

Basically I want to divide the task into two parts every time I call the function and pass each part to a new process.

Here is my code: merge.js

process.stdin.resume();
process.stdin.setEncoding('utf8');

process.stdin.on('data', function (chunk) {
    var arr = chunk.trim().split(' ');

    mergeSort(arr,0,arr.length - 1); 
  // I want to create new threads like this
  // CreateNewLeftThread
  // CreateNewRightThread
  // Join(lefThread.rightThread)


    function mergeSort(arr,left,right) {

        if (left < right) {

            var mid = Math.floor(left + (right - left)/2);
            mergeSort(arr,left,mid);
            mergeSort(arr,mid+1,right);
            merge(arr,left,right,mid);

        }

    }

    function Merge(Parameters) {

        /*Code Here*/

    }

    process.exit(0);

});