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-typevar readChunk = require('read-chunk'); // npm install read-chunk
var fileType = require('file-type');
var buffer = readChunk.sync('unicorn.png', 0, 262);
fileType(buffer);
//=> {ext: 'png', mime: 'image/png'}or from a remote location:
var http = require('http');
var fileType = require('file-type');
var url = 'http://assets-cdn.github.com/images/spinners/octocat-spinner-32.gif';
http.get(url, function (res) {
res.once('data', function (chunk) {
res.destroy();
console.log(fileType(chunk));
//=> {ext: 'gif', mime: 'image/gif'}
});
});var xhr = new XMLHttpRequest();
xhr.open('GET', 'unicorn.png');
xhr.responseType = 'arraybuffer';
xhr.onload = function () {
fileType(new Uint8Array(this.response));
//=> {ext: 'png', mime: 'image/png'}
};
xhr.send();Returns an object (or null when no match) with:
ext- one of the supported file typesmime- the MIME type
Type: buffer (Node.js), uint8array
It only needs the first 262 bytes.
$ npm install --global file-type$ file-type --help
Usage
file-type <filename>
cat <filename> | file-type
Example
cat unicorn.png | file-type
pngjpgpnggifwebptifbmpjxrpsdziptarrargzbz27zmp4mkvwebmmovavimpgmp3m4aoggflacwavpdfepubexeswfrtf
SVG isn't included as it requires the whole file to be read, but you can get it here.
PR welcome for additional commonly used file types.
MIT © Sindre Sorhus