Node.js Q & A


How do you handle file uploads in Node.js?

Handling file uploads in Node.js typically involves using middleware libraries such as multer or formidable along with Express.js to parse and process incoming multipart/form-data requests containing file uploads.


Here’s how to handle file uploads using multer middleware in an Express.js application:


Install the multer package using npm:

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npm install multer

In your Node.js application, import the multer middleware and configure it to specify the destination directory for uploaded files:

  • javascript
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const express = require('express');
const multer = require('multer');

const app = express();

// Configure multer middleware
const storage = multer.diskStorage({
 destination: 'uploads/',
 filename: (req, file, cb) => {
 cb(null, file.originalname);

const upload = multer({ storage: storage });

Define a route handler to handle file uploads using the upload middleware:

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file'), (req, res) => {
// Access uploaded file via req.file
if (!req.file) {
return res.status(400).send('No file uploaded');
res.send('File uploaded successfully');

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In the HTML form on the client-side, set the enctype attribute to multipart/form-data and include an input field of type file:

<form action="/upload" method="post" enctype="multipart/form-data">
 <input type="file" name="file">
 <button type="submit">Upload</button>

With this setup, when a user submits the form with a file selected, the multer middleware will handle parsing the multipart/form-data request and saving the uploaded file to the specified destination directory. The route handler then receives the uploaded file object in req.file and can perform further processing, such as saving the file to a database or serving it to the client.


Handling file uploads in Node.js requires careful consideration of security, file size limits, and storage requirements. Middleware libraries like multer provide options to configure these settings and ensure secure and efficient file uploads in Node.js applications.

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Experienced Principal Engineer and Fullstack Developer with a strong focus on Node.js. Over 5 years of Node.js development experience.