Hello, when working with express the first two lines of the js file are usually the following:
var express = require('express');
var app = express();
Why is it necessary to save express() in app? Why would you use not say express().use() for example?
Is this just an arbitrary convention?
I think the second answer is particularly helpful:
You will be using the same
express() instance in
app multiple times (for listening and HTTP methods (https://expressjs.com/en/starter/basic-routing.html), as it saves (stores) a single instance of the function
express into a variable.
If you do
express().use() instead along with other methods on
express(), you will be creating multiple instances/applications.
In terms of naming it
app, I guess you can name it something else, but it is convention, as you are building a web app (Express is a web application framework on node.js).
Ok, that makes sense. Thank you!