mirror of
https://github.com/thangisme/notes.git
synced 2024-11-01 00:27:24 -04:00
65 lines
1.6 KiB
Markdown
65 lines
1.6 KiB
Markdown
|
#through
|
||
|
|
|
||
|
|
[](http://travis-ci.org/dominictarr/through)
|
||
|
|
[](https://ci.testling.com/dominictarr/through)
|
||
|
|
|
||
|
|
Easy way to create a `Stream` that is both `readable` and `writable`.
|
||
|
|
|
||
|
|
* Pass in optional `write` and `end` methods.
|
||
|
|
* `through` takes care of pause/resume logic if you use `this.queue(data)` instead of `this.emit('data', data)`.
|
||
|
|
* Use `this.pause()` and `this.resume()` to manage flow.
|
||
|
|
* Check `this.paused` to see current flow state. (`write` always returns `!this.paused`).
|
||
|
|
|
||
|
|
This function is the basis for most of the synchronous streams in
|
||
|
|
[event-stream](http://github.com/dominictarr/event-stream).
|
||
|
|
|
||
|
|
``` js
|
||
|
|
var through = require('through')
|
||
|
|
|
||
|
|
through(function write(data) {
|
||
|
|
this.queue(data) //data *must* not be null
|
||
|
|
},
|
||
|
|
function end () { //optional
|
||
|
|
this.queue(null)
|
||
|
|
})
|
||
|
|
```
|
||
|
|
|
||
|
|
Or, can also be used _without_ buffering on pause, use `this.emit('data', data)`,
|
||
|
|
and this.emit('end')
|
||
|
|
|
||
|
|
``` js
|
||
|
|
var through = require('through')
|
||
|
|
|
||
|
|
through(function write(data) {
|
||
|
|
this.emit('data', data)
|
||
|
|
//this.pause()
|
||
|
|
},
|
||
|
|
function end () { //optional
|
||
|
|
this.emit('end')
|
||
|
|
})
|
||
|
|
```
|
||
|
|
|
||
|
|
## Extended Options
|
||
|
|
|
||
|
|
You will probably not need these 99% of the time.
|
||
|
|
|
||
|
|
### autoDestroy=false
|
||
|
|
|
||
|
|
By default, `through` emits close when the writable
|
||
|
|
and readable side of the stream has ended.
|
||
|
|
If that is not desired, set `autoDestroy=false`.
|
||
|
|
|
||
|
|
``` js
|
||
|
|
var through = require('through')
|
||
|
|
|
||
|
|
//like this
|
||
|
|
var ts = through(write, end, {autoDestroy: false})
|
||
|
|
//or like this
|
||
|
|
var ts = through(write, end)
|
||
|
|
ts.autoDestroy = false
|
||
|
|
```
|
||
|
|
|
||
|
|
## License
|
||
|
|
|
||
|
|
MIT / Apache2
|