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