PostCSS Random Function [][PostCSS]

npm install @csstools/postcss-random-function --save-dev

[PostCSS Random Function] lets you use the random function, following the [CSS Values 5] specification.

``css
div {
color: oklch(0.7 0.2 random(120deg, 240deg));
}

div {
color: oklch(0.7 0.2 random(120deg, 240deg, 7deg));
}

div {
margin: random(10px, 100px) random(10px, 100px);
padding: random(--padding, 10px, 100px) random(--padding, 10px, 100px);
}

/ becomes /

div {
color: oklch(0.7 0.2 177.17235deg);
}

div {
color: oklch(0.7 0.2 176deg);
}

div {
margin: 41.7525px 70.01679px;
padding: 44.03856px 44.03856px;
}
`

> [!NOTE]
> Generated values are deterministic pseudo random numbers.
> Generating values twice with the same input will give the same result.
> The input length of the CSS source file is used as a random seed.

Usage

Add [PostCSS Random Function] to your project:

`bash
npm install postcss @csstools/postcss-random-function --save-dev
`

Use it as a [PostCSS] plugin:

`js
const postcss = require('postcss');
const postcssRandomFunction = require('@csstools/postcss-random-function');

postcss([
postcssRandomFunction(/ pluginOptions /)
]).process(YOUR_CSS /, processOptions /);
`

⚠️ About custom properties

Given the dynamic nature of custom properties it's impossible to know what the variable value is, which means the plugin can't compute a final value for the stylesheet.

Because of that, any usage that contains a var is skipped.

Options

$3

The preserve option determines whether the original notation
is preserved. By default, it is not preserved.

`js
postcssRandomFunction({ preserve: true })
`

`css
div {
color: oklch(0.7 0.2 random(120deg, 240deg));
}

div {
color: oklch(0.7 0.2 random(120deg, 240deg, 7deg));
}

div {
margin: random(10px, 100px) random(10px, 100px);
padding: random(--padding, 10px, 100px) random(--padding, 10px, 100px);
}

/ becomes /

div {
color: oklch(0.7 0.2 177.17235deg);
color: oklch(0.7 0.2 random(120deg, 240deg));
}

div {
color: oklch(0.7 0.2 176deg);
color: oklch(0.7 0.2 random(120deg, 240deg, 7deg));
}

div {
margin: 41.7525px 70.01679px;
margin: random(10px, 100px) random(10px, 100px);
padding: 44.03856px 44.03856px;
padding: random(--padding, 10px, 100px) random(--padding, 10px, 100px);
}
``

[cli-url]: https://github.com/csstools/postcss-plugins/actions/workflows/test.yml?query=workflow/test
[css-url]: https://cssdb.org/#random-function
[discord]: https://discord.gg/bUadyRwkJS
[npm-url]: https://www.npmjs.com/package/@csstools/postcss-random-function

[PostCSS]: https://github.com/postcss/postcss
[PostCSS Random Function]: https://github.com/csstools/postcss-plugins/tree/main/plugins/postcss-random-function
[CSS Values 5]: https://drafts.csswg.org/css-values-5/#random