mastodon/app/assets/javascripts/components/components/dropdown_menu.jsx

import Dropdown, { DropdownTrigger, DropdownContent } from 'react-simple-dropdown';
import PureRenderMixin from 'react-addons-pure-render-mixin';

const DropdownMenu = React.createClass({

  propTypes: {
    icon: React.PropTypes.string.isRequired,
    items: React.PropTypes.array.isRequired,
    size: React.PropTypes.number.isRequired,
    direction: React.PropTypes.string
  },

  mixins: [PureRenderMixin],

  setRef (c) {
    this.dropdown = c;
  },

  render () {
    const { icon, items, size, direction } = this.props;
    const directionClass = (direction === "left") ? "dropdown__left" : "dropdown__right";

    return (
      <Dropdown ref={this.setRef}>
        <DropdownTrigger className='icon-button' style={{ fontSize: `${size}px`, width: `${size}px`, lineHeight: `${size}px` }}>
          <i className={`fa fa-fw fa-${icon}`} style={{ verticalAlign: 'middle' }} />
        </DropdownTrigger>

        <DropdownContent className={directionClass} style={{ lineHeight: '18px', textAlign: 'left' }}>
          <ul>
            {items.map(({ text, action, href = '#' }, i) => <li key={i}><a href={href} target='_blank' rel='noopener' onClick={e => {
              if (typeof action === 'function') {
                e.preventDefault();
                action();
                this.dropdown.hide();
              }
            }}>{text}</a></li>)}
          </ul>
        </DropdownContent>
      </Dropdown>
    );
  }

});

export default DropdownMenu;