How to write interactive CLI utility in node.js

Node.js is mainly a server development framework - accepting requests and responding to them over network. But sometimes need arises to write a CLI utility using node.js. The asynchronous nature of node.js can make it difficult to write a simple CLI utility that will ask series of questions and accept answers from the user. Recently I ran into such situation, here is how I wrote one. (Learnt about the ask function from this post)
gist