A Rework plugin to add user-defined mixins.

npm install rework-plugin-mixin

User-defined mixins are functions that are invoked for a given property, and passed the value. They return an object that represents one or more properties.

For example the following overflow mixin allows the designer to utilize overflow: ellipsis; to automatically assign associated properties preventing wrapping etc.

The receiver (this) is the Rework instance, allowing the mixin to reference properties such as the vendor .prefixes array.

var rework = require('rework');
var mixin = require('rework-plugin-mixin');
var css = rework(css)
  .use(mixin({ overflow: ellipsis }))
  .toString();
function ellipsis(type) {
  if ('ellipsis' == type) {
    return {
      'white-space': 'nowrap',
      'overflow': 'hidden',
      'text-overflow': 'ellipsis'
    }
  }
  return type;
}

Mixins in use look just like regular CSS properties:

h1 {
  overflow: ellipsis;
}

yields:

h1 {
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis
}

You may also return array values to expand to several definitions of the property:

function display(type) {
  if ('flex' == type) {
    return {
      display: [
        '-webkit-flex',
        '-moz-flex',
        '-webkit-flexbox',
        'flex'
      ]
    }
  }
  return {
    display: type
  }
}

Would yield:

.myclass {
  display: -webkit-flex;
  display: -moz-flex;
  display: -webkit-flexbox;
  display: flex;
}