Let’s say you have two files:

— foo.js —

module.exports = function(n) {
    return n * 111;
};

— main.js —

var foo = require('./foo.js');
console.log(foo(5));

“If an idea is obviously bad, find a cheap way to try it because if it turns out it’s not bad then it’s really interesting. If you have a good idea that’s obviously good, somebody else has probably tried it before.”

In recent years, it’s been common for JavaScript (aka EcmaScript) programmers to use Source to source compilers, also known as “transpilers”, to convert a more enhanced or modern version of the language to an earlier version that can run on older browsers.

npm install

you see this all the time in a build step, such as here: http://www.codecadwallader.com/2015/03/15/integrating-gulp-into-your-tfs-builds-and-web-deploy/