Why node.js is very important for every web developer ?

Answer 1

making my answer straight and fair that not every developer making web apps using node.js but they installed node.js for the NPM (node package manger) and to run NPM on your system you have to install node.js because NPM uses node.js runtime.
Yes NPM and Node.js is very very very useful for web development without Node.js you can't you build the system like Gulp or Grunt and moreover. in my view Currently Node.js is the most powerful tool and every web developer must have a little bit knowledge of it at least you should learn how to use.
Thank You. the above answer is my view on the topic. here we have more knowledgeable developers who can explain you this in detail

Answer 2

Nodejs is a v8 engine platform which helps client side developer to become a full stack developer. we can compile JavaScript outside the browser using nodejs engine via command line. Node js is not a programming language but allows JavaScript in server side their by we can maintain one single language in entire stack.