# 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
Generated by dwww version 1.15 on Thu Jun 27 22:50:39 CEST 2024.