JarCastingfile-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.
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 typesmime- 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 typesmime- 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 typesmime- 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 typesmime- 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
jpgpngapng- Animated Portable Network Graphicsgifwebpflifcr2- Canon Raw image file (v2)cr3- Canon Raw image file (v3)orf- Olympus Raw image filearw- Sony Alpha Raw image filedng- Adobe Digital Negative image filenef- Nikon Electronic Format image filerw2- Panasonic RAW image fileraf- Fujifilm RAW image filetifbmpicnsjxrpsdinddziptarrargzbz27zdmgmp4midmkvwebmmovavimpgmp1- MPEG-1 Audio Layer Imp2mp3oggogvogmogaspxogxopusflacwavqcpamrpdfepubmobi- Mobipocketexeswfrtfwoffwoff2eotttfotficoflvpsxzsqlitenescrxxpicabdebarrpmZlzcfbmxfmtswasmblendbpgdocxpptxxlsxjp2- JPEG 2000jpm- JPEG 2000jpx- JPEG 2000mj2- Motion JPEG 2000aifodt- OpenDocument for word processingods- OpenDocument for spreadsheetsodp- OpenDocument for presentationsxmlheiccurktxape- Monkey's Audiowv- WavPackasf- Advanced Systems Formatdcm- DICOM Image Filempc- Musepack (SV7 & SV8)ics- iCalendarglb- GL Transmission Formatpcap- Libpcap File Formatdsf- Sony DSD Stream File (DSF)lnk- Microsoft Windows file shortcutalias- macOS Alias filevoc- Creative Voice Fileac3- ATSC A/52 Audio File3gp- Multimedia container format defined by the Third Generation Partnership Project (3GPP) for 3G UMTS multimedia services3g2- Multimedia container format defined by the 3GPP2 for 3G CDMA2000 multimedia servicesm4v- MPEG-4 Visual bitstreamsm4p- MPEG-4 files with audio streams encrypted by FairPlay Digital Rights Management as were sold through the iTunes Storem4a- Audio-only MPEG-4 filesm4b- Audiobook and podcast MPEG-4 files, which also contain metadata including chapter markers, images, and hyperlinksf4v- ISO base media file format used by Adobe Flash Playerf4p- ISO base media file format protected by Adobe Access DRM used by Adobe Flash Playerf4a- Audio-only ISO base media file format used by Adobe Flash Playerf4b- Audiobook and podcast ISO base media file format used by Adobe Flash Playermie- Dedicated meta information format which supports storage of binary as well as textual meta informationshp- Geospatial vector data formatarrow- Columnar format for tables of dataaac- Advanced Audio Codingit- Audio module format: Impulse Trackers3m- Audio module format: ScreamTracker 3xm- Audio module format: FastTracker 2ai- Adobe Illustrator Artworkskp- SketchUpavif- AV1 Image File Formateps- Encapsulated PostScriptlzh- LZH archivepgp- Pretty Good Privacyasar- Archive format primarily used to enclose Electron applicationsstl- Standard Tesselated Geometry File Format (ASCII only)
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 outis-svgfor something that mostly works.
file-type for enterprise
Available as part of the Tidelift Subscription.
The maintainers of file-type and thousands of other packages are working with Tidelift to deliver commercial support and maintenance for the open source dependencies you use to build your applications. Save time, reduce risk, and improve code health, while paying the maintainers of the exact dependencies you use. Learn more.
Related
- file-type-cli - CLI for this module