@design-systems/babel-plugin-replace-styles

This babel plugin lets you overwrite CSS imports that are happening inside your design system.

Why would you want to do that?

Here's a simple example that showcases a potential use-case:

You have a Button component, built using the Design Systems CLI. It has a main.css output that gets generated when you build, and you have a single PostCSS build that generates it. Now, another team wants you to auto-prefix your CSS to support older browsers. Without this plugin, you would need to just add the prefixes and now everyone has to download those, just to support the extra use case.

OR

We could use the DS-CLI build plugin's multi-build CSS feature, and generate two CSS files: main.css and prefixed.css. The only issue is, if we turn on automatic CSS imports, everyone will get main and not prefixed.

Enter this plugin. Now the team who needs prefixed CSS can install this and configure it to replace main with prefixed if it exists. Everyone only gets the CSS they need imported, and we can still have a nice auto-import by default.

Note: This also works well with postcss-themed; you can use this plugin to swap between different css files that contain different themes!

Usage

babel.config.json:

1{
2  "plugins": [
3    [
4      "@design-systems/babel-plugin-replace-styles",
5      { "scope": "your-ds", "replace": "main", "use": "prefixed" }
6    ]
7  ]
8}

Example

Input:

1// In node_modules/my-ds/component/dist/esm/index.js
2import '../main.css';

Output:

1import '../prefixed.css';

Notes for setup:

babel-loader will not parse node_modules by default. You'll need to use babel.config.json (a .babelrc will not work), and you'll need to configure webpack to parse your node_modules. I've provided an example below:

1module: {
2  rules: [
3    {
4      include: [
5        path.join(__dirname, 'node_modules/@your-ds/'),
6        path.join(__dirname, 'src'),
7      ],
8      test: /\.(js|jsx|mjs|tsx|ts)$/,
9      loader: 'babel-loader',
10    },
11  ];
12}