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iterAdvance

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

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

## Installation

bash
npm install @stdlib/iter-advance

Alternatively,

- To load the package in a website via a script tag without installation and bundlers, use the [ES Module][es-module] available on the [esm][esm-url] branch (see [README][esm-readme]).
- If you are using Deno, visit the [deno][deno-url] branch (see [README][deno-readme] for usage intructions).
- For use in Observable, or in browser/node environments, use the [Universal Module Definition (UMD)][umd] build available on the [umd][umd-url] branch (see [README][umd-readme]).

The [branches.md][branches-url] file summarizes the available branches and displays a diagram illustrating their relationships.

To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.

## 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

## 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

## Examples

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

*

## 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 © 2016-2025. The Stdlib [Authors][stdlib-authors].