npm package: @stdlib/iter-pipeline
Description: Create an iterator pipeline.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    About stdlib...
  </summary>
  <p>We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.</p>
  <p>The library is fully decomposable, being architected in such a way that you can swap out and mix and match APIs and functionality to cater to your exact preferences and use cases.</p>
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</details>

# iterPipeline

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

> Create an [iterator][mdn-iterator-protocol] pipeline.

<!-- Section to include introductory text. Make sure to keep an empty line after the intro `section` element and another before the `/section` close. -->

<section class="intro">

</section>

<!-- /.intro -->

<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/iter-pipeline
```

</section>

<section class="usage">

## Usage

```javascript
var iterPipeline = require( '@stdlib/iter-pipeline' );
```

#### iterPipeline( iterFcn0\[, ...iterFcn] )

Returns an [iterator][mdn-iterator-protocol] pipeline.

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );
var iterThunk = require( '@stdlib/iter-pipeline-thunk' );
var iterHead = require( '@stdlib/iter-head' );
var iterSome = require( '@stdlib/iter-some' );

// Convert iterator functions to unary functions which accept an iterator:
var it1 = iterThunk( iterHead, 5 );
var it2 = iterThunk( iterSome, 3 );

// Create an iterator pipeline:
var p = iterPipeline( it1, it2 );

// Create a source iterator:
var arr = array2iterator( [ 0, 0, 1, 1, 1, 0, 0, 0, 1, 1 ] );

// Provide the source iterator to our iterator pipeline:
var bool = p( arr );
// returns true

// Create a new source iterator:
arr = array2iterator( [ 0, 0, 1, 0, 1, 0, 0, 0, 1, 1 ] );

// Run the pipeline for the new source iterator:
bool = p( arr );
// returns false
```

The function accepts [iterator][mdn-iterator-protocol] functions provided as separate arguments **or** as a single argument consisting of an array of [iterator][mdn-iterator-protocol] functions.

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );
var iterThunk = require( '@stdlib/iter-pipeline-thunk' );
var iterHead = require( '@stdlib/iter-head' );
var iterSome = require( '@stdlib/iter-some' );

var it1 = iterThunk( iterHead, 5 );
var it2 = iterThunk( iterSome, 3 );

var p = iterPipeline( [ it1, it2 ] );

var arr = array2iterator( [ 0, 0, 1, 1, 1, 0, 0, 0, 1, 1 ] );
var bool = p( arr );
// returns true

arr = array2iterator( [ 0, 0, 1, 0, 1, 0, 0, 0, 1, 1 ] );
bool = p( arr );
// returns false
```

</section>

<!-- /.usage -->

<!-- Package usage notes. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="notes">

## Notes

-   Within the context of an [iterator][mdn-iterator-protocol] pipeline (as defined by this function), an [iterator][mdn-iterator-protocol] function is defined as a **unary** function which accepts an [iterator][mdn-iterator-protocol] as its **only** argument.
-   Each [iterator][mdn-iterator-protocol] function, except the last [iterator][mdn-iterator-protocol] function, within an [iterator][mdn-iterator-protocol] pipeline must return an [iterator][mdn-iterator-protocol].
-   Starting from the left, each returned [iterator][mdn-iterator-protocol] is passed to the next [iterator][mdn-iterator-protocol] function.
-   The result of the last [iterator][mdn-iterator-protocol] function is the result of the pipeline.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

<!-- eslint-disable function-call-argument-newline, function-paren-newline -->

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

```javascript
var randu = require( '@stdlib/random-iter-randu' );
var iterHead = require( '@stdlib/iter-head' );
var iterMap = require( '@stdlib/iter-map' );
var iterSome = require( '@stdlib/iter-some' );
var iterThunk = require( '@stdlib/iter-pipeline-thunk' );
var iterPipeline = require( '@stdlib/iter-pipeline' );

function threshold( r ) {
    return ( r > 0.95 );
}

// Create a pipeline which tests whether at least 5% of values exceed a threshold:
var p = iterPipeline(
    // Apply a threshold to iterated values:
    iterThunk( iterMap, threshold ),

    // Limit the sequence to 100 values:
    iterThunk( iterHead, 100 ),

    // Test whether at least 5 values exceed the threshold:
    iterThunk( iterSome, 5 )
);

// Define the number of random number sequences to analyze:
var N = 100;

// Initialize a counter for sequences satisfying the 5% threshold:
var count = 0;

// Perform analysis...
var bool;
var i;
for ( i = 0; i < N; i++ ) {
    bool = p( randu() );
    if ( bool ) {
        count += 1;
    }
    console.log( bool );
}
console.log( '%d of %d', count, N );
```

</section>

<!-- /.examples -->

<!-- Section to include cited references. If references are included, add a horizontal rule *before* the section. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="references">

</section>

<!-- /.references -->

<!-- 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/iter-flow`][@stdlib/iter/flow]</span><span class="delimiter">: </span><span class="description">create a fluent interface for chaining together iterator methods.</span>
-   <span class="package-name">[`@stdlib/iter-pipeline-thunk`][@stdlib/iter/pipeline-thunk]</span><span class="delimiter">: </span><span class="description">create an iterator thunk.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<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>

<!-- /.stdlib -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->

<section class="links">

[npm-image]: http://img.shields.io/npm/v/@stdlib/iter-pipeline.svg
[npm-url]: https://npmjs.org/package/@stdlib/iter-pipeline

[test-image]: https://github.com/stdlib-js/iter-pipeline/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/iter-pipeline/actions/workflows/test.yml?query=branch:v0.2.3

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/iter-pipeline/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/iter-pipeline?branch=main

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[dependencies-url]: https://david-dm.org/stdlib-js/iter-pipeline/main

-->

[chat-image]: https://img.shields.io/badge/zulip-join_chat-brightgreen.svg
[chat-url]: https://stdlib.zulipchat.com

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

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

[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/iter-pipeline/tree/deno
[deno-readme]: https://github.com/stdlib-js/iter-pipeline/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/iter-pipeline/tree/umd
[umd-readme]: https://github.com/stdlib-js/iter-pipeline/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/iter-pipeline/tree/esm
[esm-readme]: https://github.com/stdlib-js/iter-pipeline/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/iter-pipeline/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/iter-pipeline/main/LICENSE

[mdn-iterator-protocol]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#The_iterator_protocol

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

[@stdlib/iter/flow]: https://www.npmjs.com/package/@stdlib/iter-flow

[@stdlib/iter/pipeline-thunk]: https://www.npmjs.com/package/@stdlib/iter-pipeline-thunk

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

</section>

<!-- /.links -->