Best Practice to create REST APIs using node.js - node.js

Question

I am from .Net and C# background and I am new to Node.js. I am working on a project, which is mix of MongoDB and Node.JS.
In MongoDB, data from various tools is stored in different different collections. I have to create multiple REST APIs using Node.JS for CRUD operation on that data, these APIs will be called from React.JS application.
I want to keep APIs into separate files for seperate tool and then calling including all files into app.js file.
Please help me with best approach.
For POC purpose, I created a node.js application, where I created app.js file and written all my code for GET|POST|DELETE APIs. This is working fine.
var _expressPackage = require("express");
var _bodyParserPackage = require("body-parser");
var _sqlPackage = require("mssql");
var app = _expressPackage();
var cors = require("cors");
var auth = require('basic-auth');
var fs = require('fs');
const nodeMailer = require('nodemailer');
//Lets set up our local server now.
var server = app.listen(process.env.PORT || 4000, function () {
var port = server.address().port;
console.log("App now running on port", port);
});
app.get("/StudentList", function(_req ,_res){
console.log("Inside StudentList");
var Sqlquery = "select * from tbl_Host where HostId='1'";
GetQueryToExecuteInDatabase(_req,_res, Sqlquery,function(err,data){
console.log(data);
});
});

Answer 1

Don't know exactly what your app intends to do, but usually if you are not serving webpages and your API is not too complex, there is no need to use express. You can build a simple server natively in NodeJS to serve data.
Additionally, if your app has many routes (or is likely to in the future), it is a good idea to put helper functions like GetQueryToExecuteInDatabase() in a separate file outside of app.js such as utils.js.
Based on what I have understood about what you want to do, your file structure should look something like this:
data (db related files)
services (contains one file per api service)
app.js
utils.js
Hope this helps.