Node Cookbook - Third Edition

Asynchronous file operations

Suppose we wanted some sort of feedback, to show that the process was doing something.

We could use an interval to write a dot to process.stdout every 10 ms.

Suppose we add the following to the top of the file:

setInterval(() => process.stdout.write('.'), 10).unref() 

This should queue a function every 10 ms that writes a dot to STDOUT.

The unref method may seem alien if we're used to using timers in the browser.

Browser timers (setTimeout and setInterval) return numbers, for IDs that can be passed into the relevant clear function. Node timers return objects, which also act as IDs in the same manner, but additionally have this handy unref method.

Simply put, the unref method prevents the timer from keeping the ...