Dynamic module loading with require

Let's say we have ./darwin.js for mac, ./win32.js for Windows in the current working directory. And we want to require one of them in ./index.js based on which platform the file is being ran. This is one of technique with require, that we can do computation inside it. Novice way of doing is the following:

if (os.platform() === "mac")
    var platform = require('./darwin.js');
else if (os.platform() === "win32")
    var platform = require('./win32.js');

Instead of above if...else conditional statments, we can write the following:

var platform = require("./" + os.platform());

nodejs 6 javascript 6 requirejs 2