It scans your HTML and JS files (you can configure which extensions it looks) and looks for words. Then it compares with words in your CSS selectors and filters out selectors without matches. If you have the word blue written in one of your JS or HTML files, it will allow a selector called .blue in your CSS. It is a simple and imperfect system, but it works.

Unlike UnCSS, the content of your other files don't matter: we're running a simple regex match against the text files instead of a parser. We're also not running any Javascript. Therefore, it is simpler, but it might produce some false-positives. If you need a more precise approach we strongly recommend UnCSS.

Caveats

Don't include CSS files in your extensions. This will make the plugin look for identifiers inside CSS files and the plugin won't optimize your code.

I'm using a simple file traversal algorithm instead of a Glob. I haven't tested it in all operating systems and environments, only the popular ones. Please file an issue and I'll look into it.

Installation:

npm install postcss-remove-unused-css

yarn add postcss-remove-unused-css

Usage

const remover = require('postcss-remove-unused-css');
postcss([remover(options)]);

See [PostCSS] docs for examples for your environment.

Options

Name	Type	Description	Default Value
path	`String`	Path to your project files	"./src"
exts	`Array`	Extensions to look into	[".js", ".jsx", ".ts", ".tsx", ".html", ".vue", ".svelte"]
whitelist	`Array`	Your whitelisted words	["html", "body"]

Using `.postcssrc`

{
  "plugins": {
    "postcss-remove-unused-css": {
      "path": "./app",
      "exts": [".js", ".html"]
    }
  }
}

Using `package.json`:

  "postcss": {
    "plugins": {
      "postcss-remove-unused-css": {
        "path": "./app",
        "exts": [".js", ".html"]
      }
    }
  },

HTML File:

<!DOCTYPE html>
<html>
  <body>
    <div class="blue bold">Hello, world!</div>
  </body>
</html>

Before

body { background: gray }
.blue { color: blue }
.red { color: red }
.pink { color: pink }
.bold { font-weight: bold }
.thin { font-weight: 100 }
.center { text-align: center }

After

body { background: gray }
.blue { color: blue }
.bold { font-weight: bold }

License

FAQs

What is postcss-remove-unused-css?

Is postcss-remove-unused-css popular?

Is postcss-remove-unused-css well maintained?

Package last updated on 28 Feb 2019

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