Introduction to state management

Anything that can be used to manage the state of a User Interface (UI) can be considered as state management. And we see examples of state management in almost every site that we use on a daily basis. You use Gmail or any other email service. And emails have a state of read or unread. If you are playing a song on Spotify, the song that you are listening to has a state of liked or not liked. Based on these states, the UI can be shown in a different manner. 

Web Components follow a similar approach. We can use a variable inside our Web Component to keep track of the state. Let's say that we want to create a Web Component that tells the user whether the device that the user is using is online or not. So, the state here will be isOnline and its value could be either online or offline. So let's begin.

Let's call this component &lt...