forked from M3-Academy/challenge-algorithms-v2.0
79 lines
1.8 KiB
Markdown
79 lines
1.8 KiB
Markdown
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# merge-stream
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Merge (interleave) a bunch of streams.
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[](http://travis-ci.org/grncdr/merge-stream)
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## Synopsis
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```javascript
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var stream1 = new Stream();
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var stream2 = new Stream();
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var merged = mergeStream(stream1, stream2);
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var stream3 = new Stream();
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merged.add(stream3);
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merged.isEmpty();
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//=> false
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```
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## Description
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This is adapted from [event-stream](https://github.com/dominictarr/event-stream) separated into a new module, using Streams3.
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## API
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### `mergeStream`
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Type: `function`
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Merges an arbitrary number of streams. Returns a merged stream.
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#### `merged.add`
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A method to dynamically add more sources to the stream. The argument supplied to `add` can be either a source or an array of sources.
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#### `merged.isEmpty`
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A method that tells you if the merged stream is empty.
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When a stream is "empty" (aka. no sources were added), it could not be returned to a gulp task.
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So, we could do something like this:
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```js
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stream = require('merge-stream')();
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// Something like a loop to add some streams to the merge stream
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// stream.add(streamA);
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// stream.add(streamB);
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return stream.isEmpty() ? null : stream;
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```
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## Gulp example
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An example use case for **merge-stream** is to combine parts of a task in a project's **gulpfile.js** like this:
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```js
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const gulp = require('gulp');
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const htmlValidator = require('gulp-w3c-html-validator');
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const jsHint = require('gulp-jshint');
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const mergeStream = require('merge-stream');
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function lint() {
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return mergeStream(
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gulp.src('src/*.html')
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.pipe(htmlValidator())
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.pipe(htmlValidator.reporter()),
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gulp.src('src/*.js')
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.pipe(jsHint())
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.pipe(jsHint.reporter())
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);
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}
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gulp.task('lint', lint);
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```
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## License
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MIT
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