how to secure api in nodejs code example

Example: How to Create a Secure REST API with Node.js and Express

/*
    This code comes from Vincent Lab
    And it has a video version linked here: https://www.youtube.com/watch?v=Tw5LupcpKS4
*/

// Import dependencie
const express = require("express");

// Setup the express server
const app = express();
const port = 3000;

// Import middlewares into express
app.use(express.json({ limit: "100mb" }));

// Import routes
const authRouter = require("./routes/auth");
const messagesRouter = require("./routes/messages");

// Setup all the routes
app.use("/api/messages", messagesRouter);
app.use("/api/auth", authRouter);

// Start the server
app.listen(port, () => {
  console.log(`Listening on port ${port}...`);
});