cssta

CSSTA

Experimental project. Basically CSS Modules, but puts the CSS in the files, because that might be useful for some projects.

Can generate real CSS files for production (with really tiny class names).

Like CSS Modules, it

• Scopes class names
• Scopes animation names

Unlike CSS Modules, it

• Does not allow variables (except for CSS var(--name), see note in composition)
• Does not include :global and :local pseudos

npm install --save cssta
npm install --save-dev babel-plugin-cssta

Usage

import cssta from 'cssta';

const styles = cssta(`
  .button {
    color: black;
  }

  .button:hover {
    color: red;
  }

  .button-large {
    font-size: 2em;
  }

  .fade {
    animation: 1s scoped-animation;
  }

  @keyframes scoped-animation {
    0% { opacity: 0 }
  }
`);

export default () => (
  <button className={`${styles.button} ${styles['button-large']}`}>Test</button>
);

In dev, this will scope all class names and insert them into style elements. The cssta(...) call will return a mapping of class name to a mangled non-conflict name. Animation names are not exported.

In production, we'll use a babel plugin that will scope all class names, generate a real CSS file, and replace the cssta(...) call with an object of the same mapping as before.

In dev mode, you can pass an optional second argument to use as a prefix for your class names to assist in debugging. In production, the second argument is ignored.

Composition

If you're going to use babel to generate real CSS files, we can't interpolate strings. I.e.

// THIS WILL NOT WORK
cssta(`
  .button {
    color: ${color};
  }
`);

You should use CSS variables to achieve this. Sidenote: interpolation only allows scoped variables, but in design, consistency is global property. It only makes sense that your globals follow that.

Calls to cssta return objects. This means your styles do not have to be in the same file as your components. It's perfectly fine to have a util file,

// util.js
export default cssta(`
  .text-center {
    text-align: center !important;
  }
`);

// button.js
import utilStyles from './util.js'

const styles = cssta(...);

export default () => (
  <button className={`${styles.button} ${utilStyles['text-center']}`}>Test</button>
);

Babel Plugin

The cssta module was designed to work in a development environment, so you don't want to use it in production. You can use babel-plugin-cssta to transform the cssta call into an object mapping and extract the CSS (and remove the import).

You can transform multiple files, and the CSS will be concatenated. However, before you run babel, you must delete the existing CSS file so you don't end up with duplicate CSS.

{
  "plugins" [
    ["babel-plugin-cssta", {
      "output": "dist/styles.css"
    }]
  ]
}

The output is relative to your current working directory.

In

const styles = cssta(`
  .button {
    color: black;
  }
`);

Out

const styles = {
  "button": "A"
};

CSS

/* File generated by babel-plugin-cssta */

.A {
  color: black;
}

Demo and Building

See cssta-demo

• Run npm start for dev mode.
• Run npm run build-cssta for prod build, and see output JS and CSS files in ./dist.