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