postcss-scoped-styles

Scope every selector within CSS with a class. Can either be a unique, randomized class per CSS file (default), or can be a class of your choosing.

Fast, lightweight, and zero dependencies.

Installation

npm i postcss-scoped-styles

// postcss.config.mjs
import postcssScopedStyles from 'postcss-scoped-styles';

export default {
  plugins: [postcssScopedStyles()],
};

Any and all selectors you use will now be scoped:

- h1 {
+ h1.gZHu1x {
    font-size: 32px;
  }

- .button {
+ .button.gZHu1x {
    color: blue;
  }

- #text-input {
+ #text-input.gZHu1x {
    font-family: monospace;
  }

However, you may opt out of this with the :global() selector (i.e. will remain as-written):

- :global(.button:hover) {
+ .button:hover {
    color: blue;
  }

It’s also important to note that html and body won’t be scoped either, as they can only appear in the document once (it also makes selecting them easier).

Options

scopedClass

By default, a random 6-character class is added for each CSS document. You may customize that by providing a scopedClass() function that returns a string:

// postcss.config.mjs
import postcssScopedStyles from 'postcss-scoped-styles';

export default {
  plugins: [
    postcssScopedStyles({
      scopedClass({ uuid, selector }) {
        return `my-scoped-class-${uuid}`; // .my-scoped-class-c10a6a
      },
    }),
  ],
};

The callback provides uuid and selector in an object param for extra context, but you don’t have to use these to generate the class. uuid is the random string that would have been applied on its own. It will be randomized on every pass, but it will stay consistent within each CSS document.