121 lines
3.9 KiB
Markdown
121 lines
3.9 KiB
Markdown
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# StreamQueue
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> StreamQueue pipe the queued streams one by one in order to preserve their content
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order.
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[](https://npmjs.org/package/streamqueue) [](https://travis-ci.org/nfroidure/StreamQueue) [](https://david-dm.org/nfroidure/streamqueue) [](https://david-dm.org/nfroidure/streamqueue#info=devDependencies) [](https://coveralls.io/r/nfroidure/StreamQueue?branch=master) [](https://codeclimate.com/github/nfroidure/StreamQueue)
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## Usage
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Install the [npm module](https://npmjs.org/package/streamqueue):
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```sh
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npm install streamqueue --save
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```
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Then, in your scripts:
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```js
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var streamqueue = require('streamqueue');
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var queue = streamqueue(
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Fs.createReadStream('input.txt'),
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Fs.createReadStream('input2.txt'),
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Fs.createReadStream('input3.txt')
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).pipe(process.stdout);
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```
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StreamQueue also accept functions returning streams, the above can be written
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like this, doing system calls only when piping:
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```js
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var streamqueue = require('streamqueue');
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var queue = streamqueue(
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Fs.createReadStream.bind(null, 'input.txt'),
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Fs.createReadStream.bind(null, 'input2.txt'),
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Fs.createReadStream.bind(null, 'input3.txt')
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).pipe(process.stdout);
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```
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Object-oriented traditionnal API offers more flexibility:
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```js
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var StreamQueue = require('streamqueue');
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var queue = new StreamQueue();
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queue.queue(
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Fs.createReadStream('input.txt'),
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Fs.createReadStream('input2.txt'),
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Fs.createReadStream('input3.txt')
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);
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queue.done();
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queue.pipe(process.stdout);
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```
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You can also chain StreamQueue methods like that:
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```js
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var StreamQueue = require('streamqueue');
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new StreamQueue()
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.queue(Fs.createReadStream('input.txt'))
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.queue(Fs.createReadStream('input2.txt'))
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.queue(Fs.createReadStream('input3.txt'))
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.done()
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.pipe(process.stdout);
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```
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You can queue new streams at any moment until you call the done() method. So the
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created stream will not fire the end event until done() call.
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Note that stream queue is compatible with the Node 0.10+ streams. For older
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streams, stream queue will wrap them with
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[`Readable.wrap`](http://nodejs.org/api/stream.html#stream_readable_wrap_stream)
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before queueing. Please fix your dependencies or report issues to libraries
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using 0.8 streams since this extra code will finally be removed.
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## API
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### StreamQueue([options], [stream1, stream2, ... streamN])
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#### options
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##### options.objectMode
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Type: `Boolean`
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Default value: `false`
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Use if piped in streams are in object mode. In this case, the stream queue will
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also be in the object mode.
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##### options.pauseFlowingStream
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Type: `Boolean`
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Default value: `true`
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If a stream is in flowing mode, then it will be paused before queueing.
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##### options.resumeFlowingStream
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Type: `Boolean`
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Default value: `true`
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If a stream is in flowing mode, then it will be resumed before piping.
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##### options.*
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StreamQueue inherits of Stream.PassThrough, the options are passed to the
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parent constructor so you can use it's options too.
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#### streamN
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Type: `Stream`
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Append streams given in argument to the queue and ends when the queue is empty.
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### StreamQueue.queue(stream1, [stream2, ... streamN])
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Append streams given in argument to the queue.
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### StreamQueue.done([stream1, stream2, ... streamN])
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Append streams given in argument to the queue and ends when the queue is empty.
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## Stats
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[](https://nodei.co/npm/streamqueue/)
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[](https://nodei.co/npm/streamqueue/)
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## Contributing
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Feel free to pull your code if you agree with publishing it under the MIT license.
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