State.init({ k: 0 }); const incK = () => { console.log("incrementing k"); State.update({ k: state.k + 1 }); }; props.setchildincrement(incK); return ( <div> root: {props.i} child: {props.j} grandchild: {state.k} <br /> <button onClick={() => { incK(); }} > grandchild + 1 </button> <br /> <button onClick={() => props.incrementparent()}>child + 1</button> </div> );