const [value, setValue] = useState(null); return ( <> <h1>{value + ""}</h1> <Widget src="andyh.near/widget/NestedProps.Child" props={{ incrementByOne: () => setValue((v) => v + 1), arr: ["oh", "hi", () => "there"], byTen: { increment: (fn) => { console.log(fn()); setValue((v) => v + 10); }, }, }} /> </> );