Express app.post() Function

The app.post() function in Express.js handles HTTP POST requests to a specific route. It defines a callback function to process incoming data sent via POST, typically used for submitting forms or sending data to a server from clients.

Syntax:

app.post(path, callback [, callback ...])

Arguments:

• Path: The path for which the middleware function is invoked and can be any of:
  • A string represents a path.
  • A path pattern.
  • A regular expression pattern to match paths.
  • An array of combinations of any of the above.
• Callback: Callback functions can be:
  • A middleware function.
  • A series of middleware functions (separated by commas).
  • An array of middleware functions.
  • A combination of all of the above.

Steps to create the application:

Step 1: You can install this package by using this command.

npm install express

Step 2: After installing the express module, you can check your express version in the command prompt using the command.

npm version express

Project Structure:

The updated dependencies in package.json file will look like:

"dependencies": {
    "express": "^4.18.2",
}

Example 1: Below is the code example of app.post() Function:

const express = require('express');
const app = express();
const PORT = 3000;

app.post('/',
    (req, res) => {
        res.send("POST Request Called")
    })

app.listen(PORT,
    function (err) {
        if (err) console.log(err);
        console.log("Server listening on PORT", PORT);
    }); 

Steps to run the program:

node index.js

Console Output:

Server listening on PORT 3000

Browser Output: Now make a POST request to http://localhost:3000/ and you will get the following output:

POST Request Called

So this is how you can use the express app.post() function which routes HTTP POST requests to the specified path with the specified callback functions.

We have a complete list of Express App methods, to check those please go through this Express.js Application Complete Reference article.