Dynamically Loading NodeJS Module

server.js

var fs = require('fs');
var path_module = require('path');
var module_holder = {};

function LoadModules(path) {
    return new Promise(resolve => {
        fs.readdirSync(path).forEach(file => {
            require(path + '/' + file)(module_holder);
        });
        resolve(module_holder);         
    });   
}

(async function() { 
    var DIR = path_module.join(__dirname, 'lib');
    module_holder = await LoadModules(DIR);
    const chokidar = require('chokidar');
        chokidar.watch(DIR, {ignored: /(^|[\/\\])\../, persistent: true})
        .on('change', path => {
            let changedModuleName = path.replace(DIR + '/','').replace('.js','');
            console.log(path + ' changed');
            delete require.cache[require.resolve(path)];
            require(path)(module_holder);
            module_holder[changedModuleName]()
        })    
})();

exports.module_holder = module_holder;

user_getDetails.js

function handler(req, res) {
    console.log('Entered my cool script!!!');
}

module.exports = function(module_holder) {
    // the key in this dictionary can be whatever you want
    // just make sure it won't override other modules
    module_holder['user_getDetails'] = handler;
};

Idea from https://stackoverflow.com/questions/10914751/loading-node-js-modules-dynamically-based-on-route

This is just PoC. It needs more error handling (eg. check if the changed path is actually a module file).