file-type
Detect the file type of a Buffer/Uint8Array/ArrayBuffer
The file type is detected by checking the magic number of the buffer.
This package is for detecting binary-based file formats, not text-based formats like .txt
, .csv
, .svg
, etc.
We accept contributions for commonly used modern file formats, not historical or obscure ones. Open an issue first for discussion.
Install
npm install file-type
This package is a ESM package. Your project needs to be ESM too. Read more.
If you use it with Webpack, you need the latest Webpack version and ensure you configure it correctly for ESM.
Usage
Node.js
Determine file type from a file:
import {fileTypeFromFile} from 'file-type';
console.log(await fileTypeFromFile('Unicorn.png'));
Determine file type from a Buffer, which may be a portion of the beginning of a file:
import {fileTypeFromBuffer} from 'file-type';
import {readChunk} from 'read-chunk';
const buffer = await readChunk('Unicorn.png', {length: 4100});
console.log(await fileTypeFromBuffer(buffer));
Determine file type from a stream:
import fs from 'node:fs';
import {fileTypeFromStream} from 'file-type';
const stream = fs.createReadStream('Unicorn.mp4');
console.log(await fileTypeFromStream(stream));
The stream method can also be used to read from a remote location:
import got from 'got';
import {fileTypeFromStream} from 'file-type';
const url = 'https://upload.wikimedia.org/wikipedia/en/a/a9/Example.jpg';
const stream = got.stream(url);
console.log(await fileTypeFromStream(stream));
Another stream example:
import stream from 'node:stream';
import fs from 'node:fs';
import crypto from 'node:crypto';
import {fileTypeStream} from 'file-type';
const read = fs.createReadStream('encrypted.enc');
const decipher = crypto.createDecipheriv(alg, key, iv);
const streamWithFileType = await fileTypeStream(stream.pipeline(read, decipher));
console.log(streamWithFileType.fileType);
const write = fs.createWriteStream(`decrypted.${streamWithFileType.fileType.ext}`);
streamWithFileType.pipe(write);
Browser
import {fileTypeFromStream} from 'file-type';
const url = 'https://upload.wikimedia.org/wikipedia/en/a/a9/Example.jpg';
const response = await fetch(url);
const fileType = await fileTypeFromStream(response.body);
console.log(fileType);
API
fileTypeFromBuffer(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:
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.
fileTypeFromFile(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:
Or undefined
when there is no match.
filePath
Type: string
The file path to parse.
fileTypeFromStream(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:
Or undefined
when there is no match.
stream
Type: stream.Readable
A readable stream representing file data.
fileTypeFromBlob(blob)
Detect the file type of a Blob
.
Note: This method is only available in the browser.
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:
Or undefined
when there is no match.
import {fileTypeFromBlob} from 'file-type';
const blob = new Blob(['<?xml version="1.0" encoding="ISO-8859-1" ?>'], {
type: 'plain/text',
endings: 'native'
});
console.log(await fileTypeFromBlob(blob));
fileTypeFromTokenizer(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:
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.
import {makeTokenizer} from '@tokenizer/http';
import {fileTypeFromTokenizer} from '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';
const httpTokenizer = await makeTokenizer(audioTrackUrl);
const fileType = await fileTypeFromTokenizer(httpTokenizer);
console.log(fileType);
Or use @tokenizer/s3
to determine the file type of a file stored on Amazon S3:
import S3 from 'aws-sdk/clients/s3';
import {makeTokenizer} from '@tokenizer/s3';
import {fileTypeFromTokenizer} from 'file-type';
const s3 = new S3();
const s3Tokenizer = await makeTokenizer(s3, {
Bucket: 'affectlab',
Key: '1min_35sec.mp4'
});
const fileType = await fileTypeFromTokenizer(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.
fileTypeStream(readableStream, options?)
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()
.
This method can be handy to put in between a stream, but it comes with a price.
Internally stream()
builds up a buffer of sampleSize
bytes, used as a sample, to determine the file type.
The sample size impacts the file detection resolution.
A smaller sample size will result in lower probability of the best file type detection.
Note: This method is only available when using Node.js.
Note: Requires Node.js 14 or later.
readableStream
Type: stream.Readable
options
Type: object
sampleSize
Type: number
Default: 4100
The sample size in bytes.
Example
import got from 'got';
import {fileTypeStream} from 'file-type';
const url = 'https://upload.wikimedia.org/wikipedia/en/a/a9/Example.jpg';
const stream1 = got.stream(url);
const stream2 = await fileTypeStream(stream1, {sampleSize: 1024});
if (stream2.fileType && stream2.fileType.mime === 'image/jpeg') {
}
readableStream
Type: stream.Readable
The input stream.
supportedExtensions
Returns a Set<string>
of supported file extensions.
supportedMimeTypes
Returns a Set<string>
of supported MIME types.
Supported file types
3g2
- Multimedia container format defined by the 3GPP2 for 3G CDMA2000 multimedia services3gp
- Multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services3mf
- 3D Manufacturing Format7z
- 7-Zip archiveZ
- Unix Compressed Fileaac
- Advanced Audio Codingac3
- ATSC A/52 Audio Fileai
- Adobe Illustrator Artworkaif
- Audio Interchange filealias
- macOS Alias fileamr
- Adaptive Multi-Rate audio codecape
- Monkey's Audioapng
- Animated Portable Network Graphicsar
- Archive filearrow
- Columnar format for tables of dataarw
- Sony Alpha Raw image fileasar
- Archive format primarily used to enclose Electron applicationsasf
- Advanced Systems Formatavi
- Audio Video Interleave fileavif
- AV1 Image File Formatblend
- Blender projectbmp
- Bitmap image filebpg
- Better Portable Graphics filebz2
- Archive filecab
- Cabinet filecfb
- Compount File Binary Formatchm
- Microsoft Compiled HTML Helpcr2
- Canon Raw image file (v2)cr3
- Canon Raw image file (v3)crx
- Google Chrome extensioncur
- Icon filedcm
- DICOM Image Filedeb
- Debian packagedmg
- Apple Disk Imagedng
- Adobe Digital Negative image filedocx
- Microsoft Worddsf
- Sony DSD Stream File (DSF)elf
- Unix Executable and Linkable Formateot
- Embedded OpenType fonteps
- Encapsulated PostScriptepub
- E-book fileexe
- Executable filef4a
- Audio-only ISO base media file format used by Adobe Flash Playerf4b
- Audiobook and podcast ISO base media file format used by Adobe Flash Playerf4p
- ISO base media file format protected by Adobe Access DRM used by Adobe Flash Playerf4v
- ISO base media file format used by Adobe Flash Playerflac
- Free Lossless Audio Codecflif
- Free Lossless Image Formatflv
- Flash videogif
- Graphics Interchange Formatglb
- GL Transmission Formatgz
- Archive fileheic
- High Efficiency Image File Formaticns
- Apple Icon imageico
- Windows icon fileics
- iCalendarindd
- Adobe InDesign documentit
- Audio module format: Impulse Trackerjp2
- JPEG 2000jpg
- Joint Photographic Experts Group imagejpm
- JPEG 2000jpx
- JPEG 2000jxl
- JPEG XL image formatjxr
- Joint Photographic Experts Group extended rangektx
- OpenGL and OpenGL ES textureslnk
- Microsoft Windows file shortcutlz
- Arhive filelzh
- LZH archivem4a
- Audio-only MPEG-4 filesm4b
- Audiobook and podcast MPEG-4 files, which also contain metadata including chapter markers, images, and hyperlinksm4p
- MPEG-4 files with audio streams encrypted by FairPlay Digital Rights Management as were sold through the iTunes Storem4v
- MPEG-4 Visual bitstreamsmid
- Musical Instrument Digital Interface filemie
- Dedicated meta information format which supports storage of binary as well as textual meta informationmj2
- Motion JPEG 2000mkv
- Matroska video filemobi
- Mobipocketmov
- QuickTime video filemp1
- MPEG-1 Audio Layer Imp2
- MPEG-1 Audio Layer IImp3
- Audio filemp4
- MPEG-4 Part 14 video filempc
- Musepack (SV7 & SV8)mpg
- MPEG-1 filemts
- MPEG-2 Transport Stream, both raw and Blu-ray Disc Audio-Video (BDAV) versionsmxf
- Material Exchange Formatnef
- Nikon Electronic Format image filenes
- Nintendo NES ROModp
- OpenDocument for presentationsods
- OpenDocument for spreadsheetsodt
- OpenDocument for word processingoga
- Audio fileogg
- Audio fileogm
- Audio fileogv
- Audio fileogx
- Audio fileopus
- Audio fileorf
- Olympus Raw image fileotf
- OpenType fontpcap
- Libpcap File Formatpdf
- Portable Document Formatpgp
- Pretty Good Privacypng
- Portable Network Graphicspptx
- Microsoft Powerpointps
- Postscriptpsd
- Adobe Photoshop documentqcp
- Tagged and chunked dataraf
- Fujifilm RAW image filerar
- Archive filerpm
- Red Hat Package Manager filertf
- Rich Text Formatrw2
- Panasonic RAW image files3m
- Audio module format: ScreamTracker 3shp
- Geospatial vector data formatskp
- SketchUpspx
- Audio filesqlite
- SQLite filestl
- Standard Tesselated Geometry File Format (ASCII only)swf
- Adobe Flash Player filetar
- Tarball archive filetif
- Tagged Image filettf
- TrueType fontvcf
- vCardvoc
- Creative Voice Filewasm
- WebAssembly intermediate compiled formatwav
- Waveform Audio filewebm
- Web video filewebp
- Web Picture formatwoff
- Web Open Font Formatwoff2
- Web Open Font Formatwv
- WavPackxcf
- eXperimental Computing Facilityxlsx
- Microsoft Excelxm
- Audio module format: FastTracker 2xml
- eXtensible Markup Languagexpi
- XPInstall filexz
- Compressed filezip
- Archive filezst
- Archive file
Pull requests are welcome for additional commonly used file types.
The following file types will not be accepted:
file-type for enterprise
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