Mithril + JSS

widget.js

Widget = {
  controller: function () {
    this.css = Widget.stylesheet().classes
  },
  view: function (ctrl) {
    return m('.widget', [
      m('h3', { class: ctrl.css.head }),
      m('div', { class: ctrl.css.body })
    ])
  },

  styles: {
    head: {
      'font-size': '3rem'
    },
    body: {
      'padding': '2rem',
      'margin': '0 0 0.5rem 0'
    }
  },

  // This could be a mixin
  stylesheet: function () {
    this._stylesheet || (this._stylesheet = jss.createStyleSheet(this.styles).attach())
    return this._stylesheet
  }
}