Dropdown.js

import React from 'react';
import { compose, withState, withHandlers } from 'recompose';

const Dropdown = ({ opened, toggleDropdown }) => (
  <div>
    <button type="button" onClick={toggleDropdown}>
      Abrir/fechar
    </button>
    <ul className={`dropdown ${opened ? 'dropdown-open' : ''}`}>
      <li>ReactJS</li>
      <li>React Native</li>
      <li>NodeJS</li>
    </ul>
  </div>
);

export default compose(
  withState('opened', 'setOpened', false),
  withHandlers({
    toggleDropdown: (props) => {
      props.setOpened(!props.opened);
    },
  }),
)(Dropdown);