type DropdownProps = {
  className: string,
  options: Array<string>
    | Array<number>
    | Array<{ label: React$Element, value: string | number }>
  onChange: Function,
  placeholder: string | Element,
  value: string | number,
  defaultValue: string | number,
  readOnly: boolean,
  optionsMaxHeight: number,
  calculateWidth: boolean,
};