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
The file type is detected by checking the magic number of the buffer.
$ npm install --save file-type
const readChunk = require('read-chunk');
const fileType = require('file-type');
const buffer = readChunk.sync('unicorn.png', 0, 4100);
fileType(buffer);
//=> {ext: 'png', mime: 'image/png'}
Or from a remote location:
const http = require('http');
const fileType = require('file-type');
const url = 'http://assets-cdn.github.com/images/spinners/octocat-spinner-32.gif';
http.get(url, res => {
res.once('data', chunk => {
res.destroy();
console.log(fileType(chunk));
//=> {ext: 'gif', mime: 'image/gif'}
});
});
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 null when no match.
Type: Buffer Uint8Array
It only needs the first 4100 bytes.
jpgpnggifwebpflifcr2tifbmpjxrpsdziptarrargzbz27zdmgmp4m4vmidmkvwebmmovaviwmvmpgmp3m4aoggopusflacwavamrpdfepubexeswfrtfwoffwoff2eotttfotficoflvpsxzsqlitenescrxxpicabdebarrpmZlzmsimxfwasmblendSVG isn't included as it requires the whole file to be read, but you can get it here.
Pull request welcome for additional commonly used file types.
MIT © Sindre Sorhus
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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