CSS Modules: Scope Locals & Extend

Transforms:

:local(.continueButton) {
color: green;
}

into:

:export {
continueButton: __buttons_continueButton_djd347adcxz9;
}
.__buttons_continueButton_djd347adcxz9 {
color: green;
}

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

importstylesfrom"./buttons.css";elem.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:

.globalButtonStyle {
background: white;
border:1px solid;
border-radius:0.25rem;
}
.globalButtonStyle:hover {
box-shadow:004px-2px;
}
:local(.continueButton) {
compose-with: globalButtonStyle;
color: green;
}

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

---

Glen Maddern, 2015.