To prevent the errors that might arise because of explicit declaration of the extension while requiring a custom module which consists of multiple JS files.
This rule aims to catch those require statements where an explicit mention of extension of given.
Examples of code which won't be catched by this rule:
const someFile = require('./someFile');
let someFile2 = require('./someFile2');
var someFile3 = require('./someFile3');
Examples of code which will be catched by this rule:
const someFile = require('./someFile.js');
let someFile2 = require('./someFile2.js');
var someFile3 = require('./someFile3.js');