In this article we will setup a Chatbot that echoes whatever we enter using Microsoft Bot Framework SDK v4 with TypeScript. We will use Yeoman to generate code that we will further enhance in upcoming posts.

The basic idea is this: You want to be informed whenever a change (mutation) on a element or its child elements occurs. A change can be a modification of an element’s attributes, its text or if there was a child node appended or removed.

Would you have any clue what an Observable is good for, just from its name? Ok, you can observe something and the ending ‘-able’ might tell you that it lazily waits for you to be observed. Right! But how? By whom? When and why?