NodeJS : async.js waterfall in node.js: how to use bind and this?

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

Here's a secret feature that I promised to disclose to you.
This is a YouTube's feature which works on Desktop.
First, Make sure this video is playing.
Then, type the letters 'awesome' on your keyboard as the next step.
Your YouTube progress bar will transform into a flashing rainbow.

Here's a brief description of who I am,
Hello there, my name is Delphi.
I am here to help you get the answers you are seeking.
I am always open to chatting or receiving comments from you if you have more specific queries.
Please feel free to share your answer or insights on the answer by leaving a comment below.
I will 'heart' your answer as a sign of appreciation.