merge2

Merge multiple streams into one stream in sequence or parallel.

# Install

Install with npm

npm install merge2

# Usage

const gulp = require('gulp')
const merge2 = require('merge2')
const concat = require('gulp-concat')
const minifyHtml = require('gulp-minify-html')
const ngtemplate = require('gulp-ngtemplate')
gulp.task('app-js', function () {
return merge2(
gulp.src('static/src/tpl/*.html')
.pipe(minifyHtml({empty: true}))
.pipe(ngtemplate({
module: 'genTemplates',
standalone: true
})
), gulp.src([
'static/src/js/app.js',
'static/src/js/locale_zh-cn.js',
'static/src/js/router.js',
'static/src/js/tools.js',
'static/src/js/services.js',
'static/src/js/filters.js',
'static/src/js/directives.js',
'static/src/js/controllers.js'
])
)
.pipe(concat('app.js'))
.pipe(gulp.dest('static/dist/js/'))
})
const stream = merge2([stream1, stream2], stream3, {end: false})
//...
stream.add(stream4, stream5)
//..
stream.end()
// equal to merge2([stream1, stream2], stream3)
const stream = merge2()
stream.add([stream1, stream2])
stream.add(stream3)
// merge order:
// 1. merge `stream1`;
// 2. merge `stream2` and `stream3` in parallel after `stream1` merged;
// 3. merge 'stream4' after `stream2` and `stream3` merged;
const stream = merge2(stream1, [stream2, stream3], stream4)
// merge order:
// 1. merge `stream5` and `stream6` in parallel after `stream4` merged;
// 2. merge 'stream7' after `stream5` and `stream6` merged;
stream.add([stream5, stream6], stream7)
// nest merge
// equal to merge2(stream1, stream2, stream6, stream3, [stream4, stream5]);
const streamA = merge2(stream1, stream2)
const streamB = merge2(stream3, [stream4, stream5])
const stream = merge2(streamA, streamB)
streamA.add(stream6)

# API

const merge2 = require('merge2')

## merge2()

## merge2(options)

## merge2(stream1, stream2, ..., streamN)

## merge2(stream1, stream2, ..., streamN, options)

## merge2(stream1, [stream2, stream3, ...], streamN, options)

return a duplex stream (mergedStream). streams in array will be merged in parallel.

## mergedStream.add(stream)

## mergedStream.add(stream1, [stream2, stream3, ...], ...)

return the mergedStream.

## mergedStream.on('queueDrain', function() {})

It will emit 'queueDrain' when all streams merged. If you set `end === false` in options, this event give you a notice that should add more streams to merge or end the mergedStream.

### stream

option Type: `Readable` or `Duplex` or `Transform` stream.

### options

option Type: `Object`.

- end - `Boolean` - if `end === false` then mergedStream will not be auto ended, you should end by yourself. Default: `undefined`
- pipeError - `Boolean` - if `pipeError === true` then mergedStream will emit `error` event from source streams. Default: `undefined`
- objectMode - `Boolean` . Default: `true`

`objectMode` and other options(`highWaterMark`, `defaultEncoding` ...) is same as Node.js `Stream`.

# License

MIT © Teambition