1// add type before parens
2React.useState<boolean>(false)
3React.useRef<HTMLDivElement>(null)
4React.useCallback(
5  function() {
6    if (theMoon) {
7      setSomethingAwesome()
8    }
9  },
10  [theMoon]
11)

1type FooProps = {
2  children: React.ReactNode
3}

1// functional
2const Foo: React.FC<FooProps> = (props) => ()
3// class
4class Foo extends React.Component<FooProps> {}

1const Foo = styled<FooProps>.div``;