What is the importance of watch command in ExtJS

I am using ExtJS 5 to create a web application.

I am also using sencha app build command to create the production build.

During development I never use sencha app watch or sencha app build commands. I just do the changes in the application code and in our web server's(tomcat) server.xml file I have given context path of the application code root folder. I just start the tomcat server and load the context by giving the context path.

Now i want to know what is the use of sencha app watch command and what are the benefits that developer is going to get using watch command.

Solution

Well, besides providing a web server, the watch command does two main things:

it rebuilds your bootstrap.js file continuously.
it provides a Fashion server

If you're trying to change the CSS for your app, by introducing a custom theme, then using Fashion and sencha app watch is a massive time saver.

You can also use Tomcat and sencha app watch in parallel, by making your Tomcat instance a proxy to the sencha app watch version.