file-type
Advanced tools
The file-type npm package is used to detect the file type of a Buffer/Uint8Array/ArrayBuffer. It supports many file types including images, audio, video, fonts, and archive formats. It is particularly useful when the file extension is unknown or has been changed, as it checks the file signature against a list of known file types.
Detecting file type from a Buffer
This feature allows you to detect the file type of a file by reading it into a Buffer and using the `fromBuffer` method to determine the file type.
const FileType = require('file-type');
const fs = require('fs');
(async () => {
const buffer = fs.readFileSync('example.png');
const fileType = await FileType.fromBuffer(buffer);
console.log(fileType);
})();Detecting file type from a stream
This feature allows you to detect the file type of a file by creating a readable stream and using the `fromStream` method to determine the file type.
const FileType = require('file-type');
const fs = require('fs');
(async () => {
const stream = fs.createReadStream('example.png');
const fileType = await FileType.fromStream(stream);
console.log(fileType);
})();Detecting file type from a file path
This feature allows you to detect the file type directly from a file path using the `fromFile` method.
const FileType = require('file-type');
(async () => {
const fileType = await FileType.fromFile('example.png');
console.log(fileType);
})();The 'mmmagic' package is an async libmagic binding for node.js for content type detection. It uses magic numbers to detect the file type, similar to file-type, but it requires libmagic to be installed on the system, which can be a downside compared to the pure JavaScript implementation of file-type.
The 'buffer-type' package is another module for detecting the content type of a Buffer. It is less popular and has fewer file signatures compared to file-type, which means it may not recognize as many file types.
The 'file-signature' package allows for identifying file types by checking their magic number signature. It is similar to file-type but has a smaller set of supported file types and a simpler API.
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 typeOr 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 typeOr 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 typeOr 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 typeOr 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)Pull requests are welcome for additional commonly used file types.
The following file types will not be accepted:
.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.Available as part of the Tidelift Subscription.
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FAQs
Detect the file type of a file, stream, or data
The npm package file-type receives a total of 9,781,443 weekly downloads. As such, file-type popularity was classified as popular.
We found that file-type demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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