Node JS Upload Multiple Files

You can upload multiple files using multer in Node.js and return their filenames. Here's how:

1. Setup Express & Multer
Install dependencies:

npm install express multer cors

2. Configure the Server
Set up an Express server with multer:

const express = require('express');
const multer = require('multer');
const cors = require('cors');

const app = express();
app.use(cors());

const storage = multer.diskStorage({
    destination: './uploads/',
    filename: (req, file, cb) => {
        cb(null, Date.now() + '-' + file.originalname);
    }
});

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

app.post('/upload', upload.array('files', 10), (req, res) => {
    const filenames = req.files.map(file => file.filename);
    res.json({ message: 'Files uploaded successfully', filenames });
});

app.listen(3000, () => console.log('Server running on port 3000'));

3. Frontend Fetch Request
Send multiple files using fetch:

<input type="file" id="fileInput" multiple>
<button onclick="uploadFiles()">Upload</button>

<script>
function uploadFiles() {
    const fileInput = document.getElementById('fileInput');
    const files = fileInput.files;
    const formData = new FormData();

    for (let file of files) {
        formData.append('files', file);
    }

    fetch('http://localhost:3000/upload', {
        method: 'POST',
        body: formData
    })
    .then(response => response.json())
    .then(data => console.log('Uploaded Files:', data.filenames))
    .catch(error => console.error('Error:', error));
}
</script>

4. Running the Project
Start your server (node server.js).

Open the HTML file in your browser.

Select multiple files and click "Upload."