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: () => setValue((v) => v + 10), // }, }} /> </> );