npm package: @stdlib/assert-is-between
Description: Test if a value is between two values.
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>
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</details>

# isBetween

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

> Test if a value is between two values.

<section class="installation">

## Installation

```bash
npm install @stdlib/assert-is-between
```

</section>

<section class="usage">

## Usage

```javascript
var isBetween = require( '@stdlib/assert-is-between' );
```

#### isBetween( value, a, b\[, left, right] )

Tests if a `value` is between two values `a` (left comparison value) and `b` (right comparison value).

```javascript
var bool = isBetween( 4, 3, 5 );
// returns true

bool = isBetween( 2, 3, 5 );
// returns false

bool = isBetween( 6, 3, 5 );
// returns false
```

By default, the function assumes that `a` and `b` are inclusive.

```javascript
var bool = isBetween( 3, 3, 5 );
// returns true

bool = isBetween( 3, 3, 5, 'closed', 'closed' );
// returns true

bool = isBetween( 5, 3, 5 );
// returns true

bool = isBetween( 5, 3, 5, 'closed', 'closed' );
// returns true
```

To make `a` and/or `b` exclusive, set the respective arguments to `'open'`.

```javascript
var bool = isBetween( 3, 3, 5, 'open', 'closed' );
// returns false

bool = isBetween( 5, 3, 5, 'closed', 'open' );
// returns false
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   If `a` and `b` are inclusive, the comparison is equivalent to

    ```text
    a <= v <= b
    ```

-   If `a` is exclusive and `b` is inclusive, the comparison is equivalent to

    ```text
    a < v <= b
    ```

-   If `a` is inclusive and `b` is exclusive, the comparison is equivalent to

    ```text
    a <= v < b
    ```

-   If `a` and `b` are exclusive, the comparison is equivalent to

    ```text
    a < v < b
    ```

-   If provided non-numeric values, comparisons are performed according to lexicographic order.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random-base-randu' );
var round = require( '@stdlib/math-base-special-round' );
var isBetween = require( '@stdlib/assert-is-between' );

var bool;
var a;
var b;
var v;
var i;

for ( i = 0; i < 100; i++ ) {
    a = round( (randu()*10.0) + 5.0 );
    b = round( (randu()*10.0) + 15.0 );
    v = round( randu()*25.0 );
    bool = isBetween( v, a, b, 'open', 'closed' );
    console.log( '%d < %d <= %d: %s', a, v, b, bool.toString() );
}
```

</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/assert-is-between-array`][@stdlib/assert/is-between-array]</span><span class="delimiter">: </span><span class="description">test if a value is an array-like object where every element is between two values.</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 -->

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<section class="links">

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

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

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

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

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/assert-is-between/main/LICENSE

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

[@stdlib/assert/is-between-array]: https://www.npmjs.com/package/@stdlib/assert-is-between-array

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

</section>

<!-- /.links -->