Express JS HTTP Methods

In Express.js, HTTP methods determine how a server handles client requests. They define the type of operation to perform on a resource, such as retrieving, creating, updating, or deleting data. Express allows defining routes that handle requests efficiently and in an organized manner.

Methods of HTTP Requests

Here are the different types of http requests

1. GET Method

The GET method is an HTTP request used by a client to retrieve data from the server. It takes two parameters: the URL to listen on and a callback function with req (client request) and res (server response) as arguments.

Syntax:

app.get("URL",(req,res)=>{})

In the above syntax

• app.get – defines a GET route in Express.
• "URL" – the path the route listens to.
• (req, res) => {} – callback function where req is the client request and res is the server response.

2. POST Method

The POST method sends data from the client to the server, usually to store it in a database. It takes two parameters: the URL to listen on and a callback function with req (client request) and res (server response). The data sent is available in the request body and must be parsed as JSON.

Syntax:

app.post("URL",(req,res)=>{})

In the above syntax

• app.post – defines a POST route in Express.
• "URL" – the path the route listens to.
• (req, res) => {} – callback function where req contains client data and res sends the server response.

3. PUT Method

The PUT method updates existing data in the database. It takes two parameters: the URL to listen on and a callback function with req (client request containing updated data in the body) and res (server response).

Syntax:

app.put("URL",(req,res)=>{})

In the above syntax:

• app.put – defines a PUT route in Express.
• "URL" – the path the route listens to.
• (req, res) => {} – callback function where req contains the client’s updated data (usually in the body) and res sends the server response.

4. DELETE Method

The DELETE method removes data from the database. It takes two parameters: the URL to listen on and a callback function with req (containing the ID of the item to delete in the body) and res (server response).

Syntax:

app.delete("URL",(req,res)=>{})

In the above syntax

• app.delete – defines a DELETE route in Express.
• "URL" – the path the route listens to.
• (req, res) => {} – callback function where req contains data (e.g., ID to delete) and res sends the server response.

5. PATCH Method

The PATCH method is used to partially update data on the server. It takes two parameters: the URL to listen on and a callback function with req (containing the data to update, usually in the body or URL parameters) and res (server response).

Syntax:

app.patch("URL", (req, res) => {})

In the above syntax:

• app.patch: defines a PATCH route in Express.
• "URL": the path the route listens to.
• (req, res) => {}: callback function where req contains the data to update (e.g., fields to change) and res sends the server response.

Example: Implementation of above HTTP methods.

const express = require('express');
const app = express();
const PORT = 3000;
app.use(express.json());

app.get("/", (req, res) => {
	console.log("GET Request Successfull!");
	res.send("Get Req Successfully initiated");
})

app.put("/put", (req, res) => {
	console.log("PUT REQUEST SUCCESSFUL");
	console.log(req.body);
	res.send(`Data Update Request Recieved`);
})

app.post("/post", (req, res) => {
	console.log("POST REQUEST SUCCESSFUL");
	console.log(req.body);
	res.send(`Data POSt Request Recieved`);
})

app.delete("/delete", (req, res) => {
	console.log("DELETE REQUEST SUCCESSFUL");
	console.log(req.body);
	res.send(`Data DELETE Request Recieved`);
})

app.listen(PORT, () => {
	console.log(`Server established at ${PORT}`);
})

Output:

Response Methods for HTTP Handlers

Express provides multiple ways to respond to requests. Besides res.send() and res.json(), you can use: