popover.js

  var Popover = React.createClass({
    mixins: [ClassNameMixin],

    className: 'Popover',

    propTypes: {
      anchorOffset: React.PropTypes.oneOf(['normal', 'fromRoundBtn', 'fromSmallRoundBtn']),
      expandFrom: React.PropTypes.shape({
        horizontal: React.PropTypes.oneOf(['left', 'center', 'right']).isRequired,
        vertical: React.PropTypes.oneOf(['top', 'bottom']).isRequired
      }),
      body: React.PropTypes.component.isRequired,
      title: React.PropTypes.renderable,
      subtitle: React.PropTypes.renderable,
      onClose: React.PropTypes.func.isRequired,
      fromEl: React.PropTypes.shape({
        getBoundingClientRect: React.PropTypes.func.isRequired
      }).isRequired
    },