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.
$ npm install file-type
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);
})();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'}
})();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.
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.
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.
Type: string
The file path to parse.
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.
Type: stream.Readable
A readable stream representing file data.
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).
Type: ITokenizer
A file source implementing the tokenizer interface.
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.
Type: stream.Readable
The input stream.
Returns a set of supported file extensions.
Returns a set of supported MIME 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)chm- Microsoft Compiled HTML Help
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.
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- file-type-cli - CLI for this module