readme.md



file-type 


Detect the file type of a Buffer/Uint8Array/ArrayBuffer


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


Install

$ npm install file-type


Usage


Node.js

Determine file type from a file:

const FileType = require('file-type');

(async () => {
    console.log(await FileType.fromFile('Unicorn.png'));
    //=> {ext: 'png', mime: 'image/png'}
})();


Determine file type from a Buffer, which may be a portion of the beginning of a file:

const FileType = require('file-type');
const readChunk = require('read-chunk');

(async () => {
    const buffer = readChunk.sync('Unicorn.png', 0, 4100);

    console.log(await FileType.fromBuffer(buffer));
    //=> {ext: 'png', mime: 'image/png'}
})();


Determine file type from a stream:

const fs = require('fs');
const FileType = require('file-type');

(async () => {
    const stream = fs.createReadStream('Unicorn.mp4');

    console.log(await FileType.fromStream(stream));
    //=> {ext: 'mp4', mime: 'video/mp4'}
}
)();


The stream method can also be used to read from a remote location:

const got = require('got');
const FileType = require('file-type');

const url = 'https://upload.wikimedia.org/wikipedia/en/a/a9/Example.jpg';

(async () => {
    const stream = got.stream(url);

    console.log(await FileType.fromStream(stream));
    //=> {ext: 'jpg', mime: 'image/jpeg'}
})();


Another stream example:

const stream = require('stream');
const fs = require('fs');
const crypto = require('crypto');
const FileType = require('file-type');

(async () => {
    const read = fs.createReadStream('encrypted.enc');
    const decipher = crypto.createDecipheriv(alg, key, iv);

    const fileTypeStream = await FileType.stream(stream.pipeline(read, decipher));

    console.log(fileTypeStream.fileType);
    //=> {ext: 'mov', mime: 'video/quicktime'}

    const write = fs.createWriteStream(`decrypted.${fileTypeStream.fileType.ext}`);
    fileTypeStream.pipe(write);
})();


Browser

const FileType = require('file-type/browser');

const url = 'https://upload.wikimedia.org/wikipedia/en/a/a9/Example.jpg';

(async () => {
    const response = await fetch(url);
    const fileType = await FileType.fromStream(response.body);

    console.log(fileType);
    //=> {ext: 'jpg', mime: 'image/jpeg'}
})();


const FileType = require('file-type/browser');

(async () => {
    const blob = new Blob(['<?xml version="1.0" encoding="ISO-8859-1" ?>'], {
        type: 'plain/text',
        endings: 'native'
    });

    console.log(await FileType.fromBlob(blob));
    //=> {ext: 'txt', mime: 'plain/text'}
})();


API


FileType.fromBuffer(buffer)

Detect the file type of a Buffer, Uint8Array, or ArrayBuffer.

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

If file access is available, it is recommended to use FileType.fromFile() instead.

Returns a Promise for an object with the detected file type and MIME type:


ext - One of the supported file types


mime - The MIME type


Or undefined when there is no match.


buffer

Type: Buffer | Uint8Array | ArrayBuffer

A buffer representing file data. It works best if the buffer contains the entire file, it may work with a smaller portion as well.


FileType.fromFile(filePath)

Detect the file type of a file path.

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

Returns a Promise for an object with the detected file type and MIME type:


ext - One of the supported file types


mime - The MIME type


Or undefined when there is no match.


filePath

Type: string

The file path to parse.


FileType.fromStream(stream)

Detect the file type of a Node.js readable stream.

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

Returns a Promise for an object with the detected file type and MIME type:


ext - One of the supported file types


mime - The MIME type


Or undefined when there is no match.


stream

Type: stream.Readable

A readable stream representing file data.


FileType.fromTokenizer(tokenizer)

Detect the file type from an ITokenizer source.

This method is used internally, but can also be used for a special "tokenizer" reader.

A tokenizer propagates the internal read functions, allowing alternative transport mechanisms, to access files, to be implemented and used.

Returns a Promise for an object with the detected file type and MIME type:


ext - One of the supported file types


mime - The MIME type


Or undefined when there is no match.

An example is @tokenizer/http, which requests data using HTTP-range-requests. A difference with a conventional stream and the tokenizer, is that it can ignore (seek, fast-forward) in the stream. For example, you may only need and read the first 6 bytes, and the last 128 bytes, which may be an advantage in case reading the entire file would take longer.

const {makeTokenizer} = require('@tokenizer/http');
const FileType = require('file-type');

const audioTrackUrl = 'https://test-audio.netlify.com/Various%20Artists%20-%202009%20-%20netBloc%20Vol%2024_%20tiuqottigeloot%20%5BMP3-V2%5D/01%20-%20Diablo%20Swing%20Orchestra%20-%20Heroines.mp3';

(async () => {
    const httpTokenizer = await makeTokenizer(audioTrackUrl);
    const fileType = await FileType.fromTokenizer(httpTokenizer);

    console.log(fileType);
    //=> {ext: 'mp3', mime: 'audio/mpeg'}
})();


Or use @tokenizer/s3 to determine the file type of a file stored on Amazon S3:

const FileType = require('file-type');
const S3 = require('aws-sdk/clients/s3');
const {makeTokenizer} = require('@tokenizer/s3');

(async () => {
    // Initialize the S3 client
    const s3 = new S3();

    // Initialize the S3 tokenizer.
    const s3Tokenizer = await makeTokenizer(s3, {
        Bucket: 'affectlab',
        Key: '1min_35sec.mp4'
    });

    // Figure out what kind of file it is.
    const fileType = await FileType.fromTokenizer(s3Tokenizer);
    console.log(fileType);
})();


Note that only the minimum amount of data required to determine the file type is read (okay, just a bit extra to prevent too many fragmented reads).


tokenizer

Type: ITokenizer

A file source implementing the tokenizer interface.


FileType.stream(readableStream)

Detect the file type of a readable stream.

Returns a Promise which resolves to the original readable stream argument, but with an added fileType property, which is an object like the one returned from FileType.fromFile().

Note: This method is only available using Node.js.


readableStream

Type: stream.Readable

The input stream.


FileType.extensions

Returns a set of supported file extensions.


FileType.mimeTypes

Returns a set of supported MIME types.


Supported file types


jpg
png

apng - Animated Portable Network Graphics
gif
webp
flif

cr2 - Canon Raw image file (v2)

cr3 - Canon Raw image file (v3)

orf - Olympus Raw image file

arw - Sony Alpha Raw image file

dng - Adobe Digital Negative image file

nef - Nikon Electronic Format image file

rw2 - Panasonic RAW image file

raf - Fujifilm RAW image file
tif
bmp
icns
jxr
psd
indd
zip
tar
rar
gz
bz2
7z
dmg
mp4
mid
mkv
webm
mov
avi
mpg

mp1 - MPEG-1 Audio Layer I
mp2
mp3
ogg
ogv
ogm
oga
spx
ogx
opus
flac
wav
qcp
amr
pdf
epub

mobi - Mobipocket
exe
swf
rtf
woff
woff2
eot
ttf
otf
ico
flv
ps
xz
sqlite
nes
crx
xpi
cab
deb
ar
rpm
Z
lz
cfb
mxf
mts
wasm
blend
bpg
docx
pptx
xlsx

jp2 - JPEG 2000

jpm - JPEG 2000

jpx - JPEG 2000

mj2 - Motion JPEG 2000
aif

odt - OpenDocument for word processing

ods - OpenDocument for spreadsheets

odp - OpenDocument for presentations
xml
heic
cur
ktx

ape - Monkey's Audio

wv - WavPack

asf - Advanced Systems Format

wma - Windows Media Audio

wmv - Windows Media Video

dcm - DICOM Image File

mpc - Musepack (SV7 & SV8)

ics - iCalendar

glb - GL Transmission Format

pcap - Libpcap File Format

dsf - Sony DSD Stream File (DSF)

lnk - Microsoft Windows file shortcut

alias - macOS Alias file

voc - Creative Voice File

ac3 - ATSC A/52 Audio File

3gp - Multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services

3g2 - Multimedia container format defined by the 3GPP2 for 3G CDMA2000 multimedia services

m4v -  MPEG-4 Visual bitstreams

m4p - MPEG-4 files with audio streams encrypted by FairPlay Digital Rights Management as were sold through the iTunes Store

m4a - Audio-only MPEG-4 files

m4b - Audiobook and podcast MPEG-4 files, which also contain metadata including chapter markers, images, and hyperlinks

f4v - ISO base media file format used by Adobe Flash Player

f4p - ISO base media file format protected by Adobe Access DRM used by Adobe Flash Player

f4a - Audio-only ISO base media file format used by Adobe Flash Player

f4b - Audiobook and podcast ISO base media file format used by Adobe Flash Player

mie - Dedicated meta information format which supports storage of binary as well as textual meta information

shp - Geospatial vector data format

arrow - Columnar format for tables of data

aac - Advanced Audio Coding

it - Audio module format: Impulse Tracker

s3m - Audio module format: ScreamTracker 3

xm - Audio module format: FastTracker 2

ai - Adobe Illustrator Artwork

skp - SketchUp

avif - AV1 Image File Format

eps - Encapsulated PostScript

lzh - LZH archive

pgp - Pretty Good Privacy

asar - Archive format primarily used to enclose Electron applications


Pull requests are welcome for additional commonly used file types.

The following file types will not be accepted:


MS-CFB: Microsoft Compound File Binary File Format based formats, too old and difficult to parse:


.doc - Microsoft Word 97-2003 Document 

.xls - Microsoft Excel 97-2003 Document 

.ppt - Microsoft PowerPoint97-2003 Document

.msi - Microsoft Windows Installer


.csv - Reason.


.svg - Detecting it requires a full-blown parser. Check out is-svg for something that mostly works.


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Related


file-type-cli - CLI for this module


Maintainers


Sindre Sorhus
Mikael Finstad
Ben Brook
Borewit