npm package: @stdlib/assert-is-duration-string
Description: Test if a value is a duration string.
Author: The Stdlib Authors
Latest version: 0.2.4

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# isDurationString

[![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 a duration string.

<section class="installation">

## Installation

```bash
npm install @stdlib/assert-is-duration-string
```

</section>

<section class="usage">

## Usage

```javascript
var isDurationString = require( '@stdlib/assert-is-duration-string' );
```

#### isDurationString( value )

Tests if a `value` is a duration `string`.

```javascript
var bool = isDurationString( '1d' );
// returns true

bool = isDurationString( '1d2h' );
// returns true
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   The function validates that a `value` is a `string`. For all other types, the function returns `false`.

-   A duration string is a string containing a sequence of time units. A time unit is a nonnegative integer followed by a unit identifier. The following unit identifiers are supported:

    -   `d`: days
    -   `h`: hours
    -   `m`: minutes
    -   `s`: seconds
    -   `ms`: milliseconds

    For example, the string `1m3s10ms` is a duration string containing three time units: `1m` (1 minute), `3s` (3 seconds), and `10ms` (10 milliseconds). The string `60m` is a duration string containing a single time unit: `60m` (60 minutes). Time units must be supplied in descending order of magnitude (i.e., days, hours, minutes, seconds, milliseconds).

-   Duration strings are case insensitive. For example, the string `1M3S10MS` is equivalent to `1m3s10ms`.

</section>

<!-- /.notes -->

<section class="examples">

## Examples

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

```javascript
var isDurationString = require( '@stdlib/assert-is-duration-string' );

var bool = isDurationString( '1h' );
// returns true

bool = isDurationString( '1m20ms' );
// returns true

bool = isDurationString( '1d 2h 3m 4s' );
// returns false

bool = isDurationString( 'beep' );
// returns false

bool = isDurationString( null );
// returns false
```

</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-duration-string-cli`][@stdlib/assert-is-duration-string-cli]</span><span class="delimiter">: </span><span class="description">CLI package for use as a command-line utility.</span>


<!-- /.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">

[@stdlib/assert-is-duration-string-cli]: https://www.npmjs.com/package/@stdlib/assert-is-duration-string-cli

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

[test-image]: https://github.com/stdlib-js/assert-is-duration-string/actions/workflows/test.yml/badge.svg?branch=v0.2.4
[test-url]: https://github.com/stdlib-js/assert-is-duration-string/actions/workflows/test.yml?query=branch:v0.2.4

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

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

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

[cli-section]: https://github.com/stdlib-js/assert-is-duration-string#cli
[cli-url]: https://github.com/stdlib-js/assert-is-duration-string/tree/cli
[@stdlib/assert-is-duration-string]: https://github.com/stdlib-js/assert-is-duration-string/tree/main

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

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

[standard-streams]: https://en.wikipedia.org/wiki/Standard_streams

[mdn-regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions

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</section>

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