Grunt

Grunt is a JavaScript task runner, a tool used to automatically perform frequent tasks such as minification, compilation, unit testing, and linting. It uses a command-line interface to run custom tasks defined in a file. Grunt was created by Ben Alman and is written in Node.js. It is distributed via NPM.
The benefits of using Grunt is - Grunt can perform repetitive tasks very easily, such as compilation, unit testing, minifying files, running tests, etc.
Grunt includes built-in tasks that extend the functionality of your plugins and scripts.
The ecosystem of Grunt is huge; you can automate anything with very less effort.