const [data, setData] = useState(""); function fallback(inp) { console.log(`<props>.fn() is null!`); } const cb = props.fn || fallback; const WrapperStyle = styled.div` display: flex; align-items: center; justify-content: center; gap: 10px; flex-direction: row; `; return ( <> <WrapperStyle> <input onChange={({ target: { value } }) => setData(value)} /> <button onClick={() => cb(data)}>Submit</button> </WrapperStyle> </> );