Compress JavaScript files with Uglify

Compressing a JavaScript file using Uglify to embed in your web app is very useful as it will allows us to reduce the overall size of a page, and hence the load times.

You already must have installed NodeJS, if you don’t, go the official web page, download and install it.

Once you have it installed, open a new terminal window and run the following command to install Uglify globally:

npm install uglify-js -g

This will allow you to use Uglify just as any other command line tool. Then using cd go to the folder where you have your JavaScript file and run the following command:

uglifyjs <js-file-name>.js --compress --mangle --output <js-file-name>.min.js

Now you can copy that new <js-file-name>.min.js file to your web app and import it, it should work as usual but you will notice that is more lightweight.

Also remember that you have to keep the original JavaScript file, because if you want to make changes to it you have to modify the original, then run the uglifyjs command again, and then update it on your web app.