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

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<details>
  <summary>
    About stdlib...
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# iterAdvance

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

> Advance an [iterator][mdn-iterator-protocol].

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<section class="intro">

</section>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

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

</section>

<section class="usage">

## Usage

```javascript
var iterAdvance = require( '@stdlib/iter-advance' );
```

#### iterAdvance( iterator\[, n] )

Eagerly advances and returns a provided [`iterator`][mdn-iterator-protocol].

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );

var arr = array2iterator( [ 0, 0, 0, 0, 1 ] );
var it = iterAdvance( arr );

var bool = ( it === arr );
// returns true

var v = it.next().done;
// returns true
```

By default, the function **eagerly** consumes an entire [`iterator`][mdn-iterator-protocol] (i.e., `n == 1e308`). To limit the number of iterations, provide a second argument.

```javascript
var array2iterator = require( '@stdlib/array-to-iterator' );

var arr = array2iterator( [ 0, 0, 0, 0, 1 ] );
var it = iterAdvance( arr, 4 );

var bool = ( it === arr );
// returns true

var v = it.next().value;
// returns 1

bool = it.next().done;
// returns true
```

</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

-   The function **eagerly** advances an input [iterator][mdn-iterator-protocol] `n` iterations or until the input [`iterator`][mdn-iterator-protocol] finishes, whichever comes first.

-   This function is equivalent to performing manual iteration using a `while` loop.

    ```javascript
    var array2iterator = require( '@stdlib/array-to-iterator' );

    var arr = array2iterator( [ 0, 0, 0, 0, 1 ] );

    var i = 0;
    var v;
    while ( i < 4 ) {
        v = arr.next();
        if ( v.done ) {
            break;
        }
        i += 1;
    }

    v = arr.next().value;
    // returns 1

    var bool = arr.next().done;
    // returns true
    ```

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random-iter-randu' );
var iterLength = require( '@stdlib/iter-length' );
var iterAdvance = require( '@stdlib/iter-advance' );

// Create an iterator which generates uniformly distributed pseudorandom numbers:
var opts = {
    'iter': 100
};
var it1 = randu( opts );

// Discard the first 10 values:
var it2 = iterAdvance( it1, 10 );

// Determine the iterator length:
var len = iterLength( it2 );
// returns 90
```

</section>

<!-- /.examples -->

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</section>

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<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/iter-head`][@stdlib/iter/head]</span><span class="delimiter">: </span><span class="description">create an iterator which returns the first `n` values of a provided iterator.</span>
-   <span class="package-name">[`@stdlib/iter-slice`][@stdlib/iter/slice]</span><span class="delimiter">: </span><span class="description">create an iterator which returns a subsequence of iterated values from a provided iterator.</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>

<!-- /.stdlib -->

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

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

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/iter-advance/main.svg
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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/iter-advance/tree/deno
[deno-readme]: https://github.com/stdlib-js/iter-advance/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/iter-advance/tree/umd
[umd-readme]: https://github.com/stdlib-js/iter-advance/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/iter-advance/tree/esm
[esm-readme]: https://github.com/stdlib-js/iter-advance/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/iter-advance/blob/main/branches.md

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

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

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

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

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

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</section>

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