Typed React children

typed-react-children.tsx

interface OptionProps {
  id: string;
}

interface SelectProps {
  children: React.FunctionComponentElement<OptionProps>[]
}

declare const Option: React.FC<OptionProps>;
declare const Select: React.FC<SelectProps>;

/**
 * All these give compile-time errors.
 */
<Select></Select>
<Select><div>Hello</div></Select>
<Select>1</Select>
<Select><Option id="42"/></Select>

/**
 * Works as expected.
 */
<Select>
  <Option id="1" />
  <Option id="2" />
</Select>