NodeJS : how to create a custom asynchronous function in node.js

To Access My Live Chat Page,
On Google, Search for "hows tech developer connect"

As promised, I have a secret feature that I want to reveal to you.
This is a YouTube's feature which works on Desktop.
First, Ensure that the video is playing before proceeding.
Then, type the letters 'awesome' on the keyboard.
It will change your youtube progress bar into a flashing rainbow.

A brief introduction of myself,
Hello, I am Delphi.
Allow me to provide support in answering your questions.
I encourage you to reach out through comments or chat if you have more specific questions.
Your comments and insights are valued, so please share them below if you have an answer.
If you provide an answer, I will 'heart' it as a sign of gratitude.