npm package: @stdlib/utils-if-then
Description: If a condition is truthy, invoke `x`; otherwise, invoke `y`.
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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# ifthen

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

> If a condition is truthy, invoke `x`; otherwise, invoke `y`.

<!-- 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>

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<!-- Package usage documentation. -->

<section class="installation">

## Installation

```bash
npm install @stdlib/utils-if-then
```

</section>

<section class="usage">

## Usage

```javascript
var ifthen = require( '@stdlib/utils-if-then' );
```

#### ifthen( bool, x, y )

If a condition is truthy, invokes `x`; otherwise, invokes `y`.

```javascript
function x() {
    return 1.0;
}

function y() {
    return -1.0;
}

var z = ifthen( true, x, y );
// returns 1.0

z = ifthen( false, x, y );
// 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

-   The function is similar to [`ifelse()`][@stdlib/utils/if-else], but allows deferred argument evaluation.

</section>

<!-- /.notes -->

<!-- Package usage examples. -->

<section class="examples">

## Examples

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

```javascript
var randu = require( '@stdlib/random-base-randu' );
var ceil = require( '@stdlib/math-base-special-ceil' );
var repeatString = require( '@stdlib/string-repeat' );
var ifthen = require( '@stdlib/utils-if-then' );

var z;
var i;

function x() {
    return repeatString( 'BOOP', ceil( randu()*3.0 ) );
}

function y() {
    return repeatString( 'beep', ceil( randu()*5.0 ) );
}

for ( i = 0; i < 100; i++ ) {
    z = ifthen( randu() > 0.9, x, y );
    console.log( z );
}
```

</section>

<!-- /.examples -->

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<section class="references">

</section>

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<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/utils-async/if-then`][@stdlib/utils/async/if-then]</span><span class="delimiter">: </span><span class="description">if a predicate function returns a truthy value, invoke `x`; otherwise, invoke `y`.</span>
-   <span class="package-name">[`@stdlib/utils-if-else`][@stdlib/utils/if-else]</span><span class="delimiter">: </span><span class="description">if a condition is truthy, return `x`; otherwise, return `y`.</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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<section class="links">

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

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

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/utils-if-then/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/utils-if-then?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/utils-if-then/tree/deno
[deno-readme]: https://github.com/stdlib-js/utils-if-then/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/utils-if-then/tree/umd
[umd-readme]: https://github.com/stdlib-js/utils-if-then/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/utils-if-then/tree/esm
[esm-readme]: https://github.com/stdlib-js/utils-if-then/blob/esm/README.md
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[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/utils-if-then/main/LICENSE

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

[@stdlib/utils/async/if-then]: https://www.npmjs.com/package/@stdlib/utils-async-if-then

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

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

</section>

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