postcss-prune-var

PostCSS plugin to remove all unused variables in a CSS file.

A --variable is considered unused if it, or any other variables consuming it are not accessed by a single var() statement in the whole CSS file.

This is unsafe if there is a possibility of a second CSS file accessing variables from the first one.

#### How does it work, and how is it different from postcss-unused-var?

- postcss-unused-var is outdated, deprecated, and didn't work right.
- Treats all variables as global, because they are.
- Removes variables from everywhere, including :root.
- Checks and prevents removal of variables only used by other variables that are accessed with var() by following variable dependency graph.
- At the same time, if a variable is only used by other unused variables, it will also be removed.
- Way faster.

Install

``
npm install postcss-prune-var --save-dev
`

Usage

`js
const pruneVar = require('postcss-prune-var');

const yourConfig = {
plugins: [pruneVar()],
};
`

Options

$3

Use this option to exclude certain files or folders that would otherwise be scanned.

`js
const pruneVar = require('postcss-prune-var');

const yourConfig = {
plugins: [pruneVar({skip: ['node_modules/**']})],
};
`


Example

Input:

`css
:root {
--root-unused: red;
--root-unused-proxy: var(--root-unused);
--root-used: blue;
}

.foo {
--unused: red;
--unused-proxy: var(--unused);
--proxied: pink;
--proxy: var(--proxied);
--used: green;
color: var(--root-used);
background: linear-gradient(to bottom, var(--used), var(--proxy));
}
`

Output

`css
:root {
--root-used: blue;
}

.foo {
--proxied: pink;
--proxy: var(--proxied);
--used: green;
color: var(--root-used);
background: linear-gradient(to bottom, var(--used), var(--proxy));
}
``