CSS Modules: Scope Locals & Extend

Transforms:

1:local(.continueButton) {
2  color: green;
3}

into:

1:export {
2  continueButton: __buttons_continueButton_djd347adcxz9;
3}
4.__buttons_continueButton_djd347adcxz9 {
5  color: green;
6}

so it doesn't pollute CSS global scope and can be simply used in JS like so:

1import styles from "./buttons.css";
2elem.innerHTML = `<button class="${styles.continueButton}">Continue</button>`;

Composition

Since we're exporting class names, there's no reason to export only one. This can give us some really useful reuse of styles:

1.globalButtonStyle {
2  background: white;
3  border: 1px solid;
4  border-radius: 0.25rem;
5}
6.globalButtonStyle:hover {
7  box-shadow: 0 0 4px -2px;
8}
9:local(.continueButton) {
10  compose-with: globalButtonStyle;
11  color: green;
12}

becomes:

.globalButtonStyle {
  background: white;
  border: 1px solid;
  border-radius: 0.25rem;
}
.globalButtonStyle:hover {
  box-shadow: 0 0 4px -2px;
}
:local(.continueButton) {
  compose-with: globalButtonStyle;
  color: green;
}

Note: you can also use composes as a shorthand for compose-with

Local-by-default & reuse across files

You're looking for CSS Modules. It uses this plugin as well as a few others, and it's amazing.

Building

npm install
npm test

• Status:
• Lines:
• Statements:

Development

• npm test:watch will watch src and test for changes and run the tests

License

ISC

With thanks

• Mark Dalgleish
• Tobias Koppers
• Guy Bedford

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Glen Maddern, 2015.