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.
$ npm install file-type
const readChunk = require('read-chunk');
const fileType = require('file-type');
const buffer = readChunk.sync('unicorn.png', 0, fileType.minimumBytes);
fileType(buffer);
//=> {ext: 'png', mime: 'image/png'}
Or from a remote location:
const http = require('http');
const fileType = require('file-type');
const url = 'https://assets-cdn.github.com/images/spinners/octocat-spinner-32.gif';
http.get(url, response => {
response.on('readable', () => {
const chunk = response.read(fileType.minimumBytes);
response.destroy();
console.log(fileType(chunk));
//=> {ext: 'gif', mime: 'image/gif'}
});
});
Or from a 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 stream = await fileType.stream(read.pipe(decipher));
console.log(stream.fileType);
//=> {ext: 'mov', mime: 'video/quicktime'}
const write = fs.createWriteStream(`decrypted.${stream.fileType.ext}`);
stream.pipe(write);
})();
const xhr = new XMLHttpRequest();
xhr.open('GET', 'unicorn.png');
xhr.responseType = 'arraybuffer';
xhr.onload = () => {
fileType(new Uint8Array(this.response));
//=> {ext: 'png', mime: 'image/png'}
};
xhr.send();
Returns an Object with:
ext - One of the supported file typesmime - The MIME typeOr undefined when there is no match.
Type: Buffer | Uint8Array | ArrayBuffer
It only needs the first .minimumBytes bytes. The exception is detection of docx, pptx, and xlsx which potentially requires reading the whole file.
Type: number
The minimum amount of bytes needed to detect a file type. Currently, it's 4100 bytes, but it can change, so don't hardcode it.
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().
Note: This method is only for Node.js.
Type: stream.Readable
jpgpnggifwebpflifcr2 - Canon Raw image file (v2)orf - Olympus Raw image filearw - Sony Alpha Raw image filedng - Adobe Digital Negative image filenef - Nikon Electronic Format image filetifbmpjxrpsdziptarrargzbz27zdmgmp4midmkvwebmmovaviwmvmpgmp2mp3m4aoggopusflacwavqcpamrpdfepubmobi - Mobipocketexeswfrtfwoffwoff2eotttfotficoflvpsxzsqlitenescrxxpicabdebarrpmZlzmsimxfmtswasmblendbpgdocxpptxxlsxjp2 - 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 Formatwma - Windows Media Audiowmv - Windows Media Videodcm - 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 PlayerSVG isn't included as it requires the whole file to be read, but you can get it here.
Pull requests are welcome for additional commonly used file types.
MIT
FAQs
Detect the file type of a file, stream, or data
The npm package file-type receives a total of 19,719,414 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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