@types/multer

What is @types/multer?

The @types/multer package provides TypeScript type definitions for Multer, a node.js middleware for handling multipart/form-data, primarily used for uploading files. It allows developers to use Multer in TypeScript projects with type checking, enabling better development experience and error handling.

What are @types/multer's main functionalities?

File Upload

This feature allows for the uploading of files. The code sample demonstrates how to set up a simple file upload endpoint using Express and Multer, where files are saved to the 'uploads/' directory.

import express from 'express';
import multer from 'multer';

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

app.post('/upload', upload.single('file'), function (req, res) {
  console.log(req.file);
  res.send('File uploaded successfully.');
});

Multiple Files Upload

This feature supports the uploading of multiple files in a single request. The code sample shows how to configure an endpoint to accept a maximum of 5 files using the `upload.array` method.

import express from 'express';
import multer from 'multer';

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

app.post('/upload', upload.array('files', 5), function (req, res) {
  console.log(req.files);
  res.send('Files uploaded successfully.');
});

File Filtering

This feature allows for filtering files based on specific criteria, such as file type. The code sample demonstrates how to accept only JPEG files using a custom file filter.

import express from 'express';
import multer from 'multer';

const fileFilter = (req, file, cb) => {
  if (file.mimetype === 'image/jpeg') {
    cb(null, true);
  } else {
    cb(new Error('Only JPEG files are allowed!'), false);
  }
};

const upload = multer({ dest: 'uploads/', fileFilter });
const app = express();

app.post('/upload', upload.single('file'), function (req, res) {
  res.send('File uploaded successfully.');
});

Other packages similar to @types/multer

formidable

Formidable is a Node.js module for parsing form data, especially file uploads. It differs from Multer in that it's lower level, providing a more flexible API for parsing incoming form data, including file uploads, but requires more setup compared to Multer.

busboy

Busboy is a fast, streaming parser for HTML form data for Node.js, focusing on performance. It's similar to Multer in handling file uploads but is more stream-oriented, making it suitable for handling large files or high volumes of data efficiently.

README

Installation

npm install --save @types/multer

Summary

This package contains type definitions for multer (https://github.com/expressjs/multer).

Details

Files were exported from https://github.com/DefinitelyTyped/DefinitelyTyped/tree/master/types/multer.

Additional Details

• Last updated: Wed, 07 Jul 2021 00:01:45 GMT
• Dependencies: @types/express
• Global values: none

Credits

These definitions were written by jt000, vilicvane, David Broder-Rodgers, Michael Ledin, HyunSeob Lee, Pierre Tchuente, Oliver Emery, and Piotr Błażejewicz.