Stream File Type

Get the file type by inspecting a stream.

Usage

``js
import fs from 'node:fs'
import FileType from 'stream-file-type'

const input = fs.createReadStream('cat.jpg')
const detector = new FileType()

// Listen for event...
detector.on('file-type', (fileType) => {
if (fileType === null) {
console.log(The mime type of "cat.jpg" could not be determined)
} else {
console.log(The file "cat.jpg" has the "${fileType.mime}" mime type)
}
})

// ...or get a Promise
detector.fileTypePromise().then((fileType) => {
if (fileType === null) {
console.log(The mime type of "cat.jpg" could not be determined)
} else {
console.log(The file "cat.jpg" has the "${fileType.mime}" mime type)
}
})

input.pipe(detector).resume()
`

API

$3

Returns a new DuplexStream that will detect the file type of the content passing thru. All the data is passed as-is right thru the stream, and can be further piped to another destination.

When enough bytes have come thru to determine the file type (currently 4100) the event file-type will be emitted with the result of the detection. The result will either be null or an object with ext and mime.

- ext - One of the supported file types
- mime - The MIME type

$3

Returns a Promise of the detected file type. If the file-type` event has already been emitted, the promise will be resolved with the result, otherwise the promise will be resolved when the file-type is detected.