npm package: @stdlib/streams-node-join
Description: Transform stream which joins streamed data.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
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</details>

# Join Stream

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> [Transform stream][transform-stream] which joins streamed data.

<section class="installation">

## Installation

```bash
npm install @stdlib/streams-node-join
```

</section>

<section class="usage">

## Usage

```javascript
var joinStream = require( '@stdlib/streams-node-join' );
```

<a name="join-stream"></a>

#### joinStream( \[options] )

Creates a [transform stream][transform-stream] which joins streamed data.

```javascript
var stdout = require( '@stdlib/streams-node-stdout' );

var stream = joinStream();

stream.pipe( stdout );

stream.write( '1' );
stream.write( '2' );
stream.write( '3' );

stream.end();

// prints: 1\n2\n3
```

The function accepts the following `options`:

-   **sep**: separator used to join streamed data. Default: `'\n'`.
-   **objectMode**: specifies whether a [stream][stream] should operate in object mode. Default: `false`.
-   **encoding**: specifies how `Buffer` objects should be decoded to `strings`. Default: `null`.
-   **highWaterMark**: specifies the `Buffer` level at which `write()` calls start returning `false`.
-   **allowHalfOpen**: specifies whether a [stream][stream] should remain open even if one side ends. Default: `false`.
-   **readableObjectMode**: specifies whether the readable side should be in object mode. Default: `false`.

To set [stream][stream] `options`,

```javascript
var opts = {
    'sep': ',',
    'objectMode': true,
    'encoding': 'utf8',
    'highWaterMark': 64,
    'allowHalfOpen': true,
    'readableObjectMode': false // overridden by `objectMode` option when `objectMode=true`
};

var stream = joinStream( opts );
```

#### joinStream.factory( \[options] )

Returns a `function` for creating [streams][transform-stream] which are identically configured according to provided `options`.

```javascript
var opts = {
    'sep': '\t',
    'objectMode': true,
    'encoding': 'utf8',
    'highWaterMark': 64
};

var factory = joinStream.factory( opts );

// Create 10 identically configured streams...
var streams = [];
var i;
for ( i = 0; i < 10; i++ ) {
    streams.push( factory() );
}
```

This method accepts the same `options` as [`joinStream()`](#join-stream).

#### joinStream.objectMode( \[options] )

This method is a convenience function to create [streams][stream] which **always** operate in `objectMode`.

```javascript
var stdout = require( '@stdlib/streams-node-stdout' );

var stream = joinStream.objectMode({
    'sep': ','
});

stream.pipe( stdout );

stream.write( 'a' );
stream.write( 'b' );
stream.write( 'c' );

stream.end();

// prints: a,b,c
```

This method accepts the same `options` as [`joinStream()`](#join-stream); however, the method will **always** override the [objectMode][object-mode] option in `options`.

</section>

<!-- /.usage -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error" -->

```javascript
var splitStream = require( '@stdlib/streams-node-split' );
var inspectStream = require( '@stdlib/streams-node-inspect-sink' );
var joinStream = require( '@stdlib/streams-node-join' );

var inspect;
var split;
var join;
var i;

function log( chunk ) {
    console.log( chunk.toString() );
}

// Create a split stream for tab delimited data:
split = splitStream({
    'sep': /\t/
});

// Create a stream to make newline delimited data:
join = joinStream({
    'sep': '\n'
});

// Create a stream to inspect joined output:
inspect = inspectStream( log );

// Create a stream pipeline:
split
    .pipe( join )
    .pipe( inspect );

// Write values to the split stream...
for ( i = 0; i < 10; i++ ) {
    split.write( i+'\t', 'utf8' );
}
split.end();
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/streams-node/split`][@stdlib/streams/node/split]</span><span class="delimiter">: </span><span class="description">transform stream which splits streamed data.</span>

</section>

<!-- /.related -->

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<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

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[stdlib]: https://github.com/stdlib-js/stdlib

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[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/streams-node-join/tree/deno
[deno-readme]: https://github.com/stdlib-js/streams-node-join/blob/deno/README.md
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/streams-node-join/main/LICENSE

[stream]: https://nodejs.org/api/stream.html

[transform-stream]: https://nodejs.org/api/stream.html

[object-mode]: https://nodejs.org/api/stream.html#stream_object_mode

<!-- <related-links> -->

[@stdlib/streams/node/split]: https://www.npmjs.com/package/@stdlib/streams-node-split

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</section>

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