npm package: @stdlib/utils-shift
Description: Remove and return the first element of a collection.
Author: The Stdlib Authors
Latest version: 0.2.3

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

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

> Remove and return the first element of a collection.

<!-- 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/utils-shift
```

</section>

<section class="usage">

## Usage

```javascript
var shift = require( '@stdlib/utils-shift' );
```

#### shift( collection )

Removes and returns the first element of a `collection`. A `collection` may be either an [`Array`][mdn-array], [`Typed Array`][mdn-typed-array], or an array-like [`Object`][mdn-object] (i.e., an [`Object`][mdn-object] having a valid writable `length` property).

```javascript
var arr = [ 1.0, 2.0, 3.0, 4.0, 5.0 ];

var out = shift( arr );
// returns [ [ 2.0, 3.0, 4.0, 5.0 ], 1.0 ]

var bool = ( out[ 0 ] === arr );
// returns true

var lastValue = out[ 1 ];
// returns 1.0
```

In contrast to [`Array.prototype.shift`][mdn-array-shift] which returns only the removed element, the function also returns the shortened collection. For [typed arrays][mdn-typed-array] having a length greater than `0`, the returned collection is a new [typed array][mdn-typed-array] view.

```javascript
var Float64Array = require( '@stdlib/array-float64' );

var arr = new Float64Array( 2 );
arr[ 0 ] = 1.0;
arr[ 1 ] = 2.0;

var out = shift( arr );
// returns [ <Float64Array>[ 2.0 ], 1.0 ]

var bool = ( out[ 0 ] === arr );
// returns false

bool = ( out[ 0 ].buffer === arr.buffer );
// returns true

var lastValue = out[ 1 ];
// returns 1.0
```

</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

-   When provided a [typed array][mdn-typed-array], the function does **not** change the underlying [`ArrayBuffer`][mdn-arraybuffer]. The function returns a new [typed array][mdn-typed-array] view whose length is one less than the input [typed array][mdn-typed-array] length. Accordingly, the function does **not** reduce the memory footprint of an input [typed array][mdn-typed-array].

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var Float64Array = require( '@stdlib/array-float64' );
var shift = require( '@stdlib/utils-shift' );

var arr;
var out;
var i;

arr = new Float64Array( 100 );
for ( i = 0; i < 100; i++ ) {
    out = shift( arr );
    arr = out[ 0 ];
    console.log( 'Length: %d', arr.length );
}
console.log( arr );
```

</section>

<!-- /.examples -->

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</section>

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<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/utils-pop`][@stdlib/utils/pop]</span><span class="delimiter">: </span><span class="description">remove and return the last element of a collection.</span>
-   <span class="package-name">[`@stdlib/utils-push`][@stdlib/utils/push]</span><span class="delimiter">: </span><span class="description">add one or more elements to the end of a collection.</span>
-   <span class="package-name">[`@stdlib/utils-unshift`][@stdlib/utils/unshift]</span><span class="delimiter">: </span><span class="description">add one or more elements to the beginning of a collection.</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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[npm-url]: https://npmjs.org/package/@stdlib/utils-shift

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

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-shift/main/LICENSE

[mdn-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array

[mdn-array-shift]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/shift

[mdn-typed-array]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Typed_arrays

[mdn-arraybuffer]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/ArrayBuffer

[mdn-object]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object

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

[@stdlib/utils/pop]: https://www.npmjs.com/package/@stdlib/utils-pop

[@stdlib/utils/push]: https://www.npmjs.com/package/@stdlib/utils-push

[@stdlib/utils/unshift]: https://www.npmjs.com/package/@stdlib/utils-unshift

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