1#through 2 3[](http://travis-ci.org/dominictarr/through) 4[](https://ci.testling.com/dominictarr/through) 5 6Easy way to create a `Stream` that is both `readable` and `writable`. 7 8* Pass in optional `write` and `end` methods. 9* `through` takes care of pause/resume logic if you use `this.queue(data)` instead of `this.emit('data', data)`. 10* Use `this.pause()` and `this.resume()` to manage flow. 11* Check `this.paused` to see current flow state. (`write` always returns `!this.paused`). 12 13This function is the basis for most of the synchronous streams in 14[event-stream](http://github.com/dominictarr/event-stream). 15 16``` js 17var through = require('through') 18 19through(function write(data) { 20 this.queue(data) //data *must* not be null 21 }, 22 function end () { //optional 23 this.queue(null) 24 }) 25``` 26 27Or, can also be used _without_ buffering on pause, use `this.emit('data', data)`, 28and this.emit('end') 29 30``` js 31var through = require('through') 32 33through(function write(data) { 34 this.emit('data', data) 35 //this.pause() 36 }, 37 function end () { //optional 38 this.emit('end') 39 }) 40``` 41 42## Extended Options 43 44You will probably not need these 99% of the time. 45 46### autoDestroy=false 47 48By default, `through` emits close when the writable 49and readable side of the stream has ended. 50If that is not desired, set `autoDestroy=false`. 51 52``` js 53var through = require('through') 54 55//like this 56var ts = through(write, end, {autoDestroy: false}) 57//or like this 58var ts = through(write, end) 59ts.autoDestroy = false 60``` 61 62## License 63 64MIT / Apache2 65
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