type DropdownProps = {
  expanded: boolean,
  value: string | number,
  options: { [optionValue: string | number]: string | React$Element },
};

const Dropdown = props => (
  <div>
    <button aria-haspopup="true" aria-expanded={props.expanded}>
      {props.options[props.value]}
    </button>
    <ul aria-hidden={!props.expanded}>
      {Object.keys(props.options).map(value => (
        <li key={value}>
          {props.options[value]}
        </li>
      ))}
    </ul>
  </div>
);