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merge-stream

Merge (interleave) a bunch of streams.

# Synopsis

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 separated into a new module, using Streams3.

# API

## <tt>mergeStream</tt>

Type: `function`

Merges an arbitrary number of streams. Returns a merged stream.

### <tt>merged.add</tt>

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.

### <tt>merged.isEmpty</tt>

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:

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:

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