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  • License MIT

Detect the file type of a Buffer/Uint8Array

Package Exports

  • @marklb/file-type

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@marklb/file-type) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

file-type Build Status

Detect the file type of a Buffer/Uint8Array

The file type is detected by checking the magic number of the buffer.

This repository is a fork of sindresorhus/file-type with ES5 build. IE couldn't load the script and the projects using this package are not configured to transpile dependencies. Also started making a types file for typescript, but it isn't complete.

Install

$ npm install file-type

Usage

Node.js
const readChunk = require('read-chunk');
const fileType = require('file-type');

const buffer = readChunk.sync('unicorn.png', 0, fileType.minimumBytes);

fileType(buffer);
//=> {ext: 'png', mime: 'image/png'}

Or from a remote location:

const http = require('http');
const fileType = require('file-type');

const url = 'http://assets-cdn.github.com/images/spinners/octocat-spinner-32.gif';

http.get(url, response => {
    response.on('readable', () => {
        const chunk = response.read(fileType.minimumBytes);
        response.destroy();
        console.log(fileType(chunk));
        //=> {ext: 'gif', mime: 'image/gif'}
    });
});
Browser
const xhr = new XMLHttpRequest();
xhr.open('GET', 'unicorn.png');
xhr.responseType = 'arraybuffer';

xhr.onload = () => {
    fileType(new Uint8Array(this.response));
    //=> {ext: 'png', mime: 'image/png'}
};

xhr.send();

API

fileType(input)

Returns an Object with:

Or null when no match.

input

Type: Buffer Uint8Array

It only needs the first .minimumBytes bytes. The exception is detection of docx, pptx, and xlsx which potentially requires reading the whole file.

fileType.minimumBytes

Type: number

The minimum amount of bytes needed to detect a file type. Currently, it's 4100 bytes, but it can change, so don't hardcode it.

Supported file types

SVG isn't included as it requires the whole file to be read, but you can get it here.

Pull request welcome for additional commonly used file types.

Created by

License

MIT