expressjsHow can I use Express.js and Multer to upload files?

Express.js and Multer can be used together to upload files. Multer is a Node.js middleware for handling multipart/form-data, which is primarily used for uploading files.

Example code

const express = require('express');
const multer = require('multer');
const upload = multer({ dest: 'uploads/' });

const app = express();

app.post('/upload', upload.single('myFile'), (req, res, next) => {
  const file = req.file;
  if (!file) {
    const error = new Error('Please upload a file');
    error.httpStatusCode = 400;
    return next(error);
  }
  res.send(file);
});

This example code will create an Express.js application with a single route that will accept a single file upload. The file will be uploaded to the uploads/ directory and the file will be sent back as a response.

Code explanation

1. const express = require('express'); - Require the Express.js module.
2. const multer = require('multer'); - Require the Multer module.
3. const upload = multer({ dest: 'uploads/' }); - Create a Multer instance with the destination folder set to uploads/.
4. app.post('/upload', upload.single('myFile'), (req, res, next) => { - Create a POST route for /upload and use the Multer instance to accept a single file upload named myFile.
5. const file = req.file; - Get the file from the request.
6. if (!file) { - Check if a file was uploaded.
7. res.send(file); - Send the file back as a response.

Helpful links

• Express.js
• Multer

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