The document outlines the benefits of using Express.js, including reduced code, improved project structure, and extensive plugin availability. It provides a basic example of setting up an Express application, defining routes, and illustrating how to structure code effectively. Additionally, it touches on middleware, cookies, and sessions for managing client and server data.

1. Express.JS

2. How does express help you?
● Less code
● Promotes a better project structure
● Widely used. Has lots of plugins

3. Your First Express
Application

4. Your machine is the
localhost
Hostname: localhost
IP Address: 127.0.0.1

6. GET POST
PUT DELETE
PATCH
Methods

7. import express from "express";
const app = express();
app.get("/", (req, res)=>{
return res.send("Home");
}
app.listen(5000, ()=>{
console.log("Listening on PORT 5000");
});
Get the default export
from the express package
Create an Express
application
Set up your routes
Set the server up to listen
To HTTP requests

8. import fetch from 'node-fetch';
app.get("/post/rand", (req, res)=>{
const response = await fetch('https://dummyjson.com/posts');
const posts = await response.json();
const rand = Math.random() * posts.length;
for (let i = posts.length - 1; i > 0; i--) {
const j = Math.floor(Math.random() * (i + 1));
const temp = posts[i];
posts[i] = posts[j];
posts[j] = temp;
}
const randomPosts = posts.subarray(0, rand);
return res.json({posts: randomPosts);
});

9. .
├── src/
│ └── routers/
│ └── hello.js
└── server.js
Structure your code

10. "post/:id”
Route Parameters

11. Specificity
Be more
Specific
As you go
up
app.get("/:hello/world", (_req, res)=>{
res.send('YO MAMA!');
});
app.get("/:hello/", (_req, res)=>{
res.send('SO!');
});
app.get("/", (_req, res)=>{
res.send('FAT!');
});

12. .
├── src/
│ ├── routers/
│ │ ├── hello.js
│ │ ├── post.js
│ │ └── index.js
│ └── controllers/
│ ├── hello/
│ │ └── get.js
│ ├── post/
│ │ ├── get.js
│ │ └── post.js
│ └── index.js
└── server.js
Structure your code
Again!

13. Extras
You don’t need them now, but you will

14. Middlewares
Router Middleware 1 Middleware 2
{could be more}
Controller

15. Cookies and Sessions
● Cookies are used to store data on the
client side.
Who am I speaking to?
● Sessions are used to store data on the
server side.

16. Static Folder
Direct access for clients.