README.md
# mime-stream
[](https://github.com/meyfa/mime-stream/actions/workflows/main.yml)
[](https://codeclimate.com/github/meyfa/mime-stream/test_coverage)
[](https://codeclimate.com/github/meyfa/mime-stream/maintainability)
Node pass-through stream for MIME type detection.
## DEPRECATION
This package depends on [`sindresorhus/file-type`](https://www.npmjs.com/package/file-type),
adding its own interface on top.
Nowadays, `file-type` provides a pass-through stream right out of the box.
Hence, this package has become obsolete. It will _at most_ receive critical
security updates.
**Do not use `mime-stream` in new projects, and migrate old projects away.**
## Install
```
npm i mime-stream
```
## Usage
### Event: 'type'
This event is emitted as soon as the type is detected. If the type remains
unknown, `null` is passed to the event handler instead of an object.
It is guaranteed that there is always exactly one `type` event emitted, even
when the stream is closed prematurely.
Example:
```javascript
const fs = require('fs')
const MimeStream = require('mime-stream')
const stream = new MimeStream()
stream.on('type', function (type) {
console.log(type) // { ext: 'png', mime: 'image/png' }
})
fs.createReadStream('myimage.png').pipe(stream)
```
You could also add more `.pipe()` calls to the chain. `MimeStream` is
non-destructive and passes on any data it receives.
### Listener Function
This is the same as binding a function to the `type` event, just more
concise.
Example:
```javascript
const fs = require('fs')
const MimeStream = require('mime-stream')
// `new` is optional anyway
fs.createReadStream('myimage.png').pipe(MimeStream((type) => {
console.log(type) // { ext: 'png', mime: 'image/png' }
}))
```
### Property
After detection, the detection result is also available inside the `type`
property. Example:
```javascript
stream.on('end', function () {
console.log(stream.type) // { ext: 'png', mime: 'image/png' }
})
```