# merge2

> Merge multiple streams into one stream in sequence or parallel.

Latest version **1.4.1** (published 2020-06-03) · MIT license · 0 weekly downloads

## Install

```sh
npm install merge2
pnpm add merge2
yarn add merge2
bun add merge2
```

## Health

**Score 33/100 (F)** — status: abandoned.

Positive: has types package; no vulnerabilities; high quality score.

Warnings: low downloads; no esm support.

Negative: abandoned.

## Facts

| | |
|---|---|
| Version | 1.4.1 |
| Published | 2020-06-03 |
| First published | 2014-10-19 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | separate (@types/merge2) |
| Module format | CommonJS |
| Node | >= 8 |
| Dependencies | 0 |
| Unpacked size | 8.7 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 171 |
| Maintainers | zensh |
| Keywords | merge2, multiple, sequence, parallel, merge, stream, merge stream, sync |

## Links

- npm: https://www.npmjs.com/package/merge2
- Repository: https://github.com/teambition/merge2
- Issues: https://github.com/teambition/merge2/issues
- npm.io page: https://npm.io/package/merge2

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## Recent versions

- 1.4.1 (latest) — 2020-06-03
- 1.4.0 — 2020-06-03
- 1.3.0 — 2019-09-13
- 1.2.4 — 2019-07-31
- 1.2.3 — 2018-10-13
- 1.2.2 — 2018-05-04
- 1.2.1 — 2018-01-09
- 1.2.0 — 2017-09-09
- 1.1.0 — 2017-07-02
- 1.0.3 — 2016-12-31
- 1.0.2 — 2016-04-04
- 1.0.1 — 2016-02-03
- 0.3.7 — 2016-02-03
- 1.0.0 — 2016-01-19
- 0.3.6 — 2015-06-28
- … 8 more at https://npm.io/package/merge2/versions

## README

# merge2

Merge multiple streams into one stream in sequence or parallel.

[![NPM version][npm-image]][npm-url]
[![Build Status][travis-image]][travis-url]
[![Downloads][downloads-image]][downloads-url]

## Install

Install with [npm](https://npmjs.org/package/merge2)

```sh
npm install merge2
```

## Usage

```js
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/'))
})
```

```js
const stream = merge2([stream1, stream2], stream3, {end: false})
//...
stream.add(stream4, stream5)
//..
stream.end()
```

```js
// equal to merge2([stream1, stream2], stream3)
const stream = merge2()
stream.add([stream1, stream2])
stream.add(stream3)
```

```js
// 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)
```

```js
// 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

```js
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](https://www.teambition.com)

[npm-url]: https://npmjs.org/package/merge2
[npm-image]: http://img.shields.io/npm/v/merge2.svg

[travis-url]: https://travis-ci.org/teambition/merge2
[travis-image]: http://img.shields.io/travis/teambition/merge2.svg

[downloads-url]: https://npmjs.org/package/merge2
[downloads-image]: http://img.shields.io/npm/dm/merge2.svg?style=flat-square

---
_Source: https://npm.io/package/merge2 · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._