PostCSS Global Data

npm install @csstools/postcss-global-data --save-dev

PostCSS Global Data lets you inject CSS that is removed again before the final output. This is useful for plugins that use global CSS as data.

For example, in the case of CSS Modules with PostCSS Custom Media, rules are usually not imported by every single file, so PostCSS Custom Media cannot generate fallbacks. By providing a list of files, this plugin will inject the global CSS as data so that PostCSS Custom Media can generate fallbacks.

It is important that PostCSS Global Data is used before the plugin that actually needs the data.

Please note that PostCSS Global Data does not add anything to the output of your CSS. It only injects data into PostCSS so that other plugins can actually use it.

Usage

Add PostCSS Global Data to your project:

npm install postcss @csstools/postcss-global-data --save-dev

Use it as a PostCSS plugin:

const postcss = require('postcss');
const postcssGlobalData = require('@csstools/postcss-global-data');

postcss([
    postcssGlobalData(/* pluginOptions */)
]).process(YOUR_CSS /*, processOptions */);

Options

files

The files option determines which files to inject into PostCSS.

postcssGlobalData({ 
    files: [
        './src/css/variables.css',
        './src/css/media-queries.css',
    ],
});

Plugin order control with lateRemover

The lateRemover option gives you more options when ordering plugins.

// esm
import postcss from 'postcss';
import postcssGlobalData from '@csstools/postcss-global-data';

const [globalData, globalDataLateRemover] = postcssGlobalData({ 
    files: [
        './src/css/variables.css',
        './src/css/media-queries.css',
    ],
    lateRemover: true
}).plugins

postcss([
    globalData,
    /* other plugins */
    globalDataLateRemover
]).process(YOUR_CSS /*, processOptions */);

prepend

The prepend option determines if injected CSS is appended or prepended.
Defaults to false.

[!Warning] Prepending styles before @import statements will create broken stylesheets.

postcssGlobalData({ 
    files: [
        './src/css/variables.css',
        './src/css/media-queries.css',
    ],
    prepend: true
});