自定义 Hook #

import React, { useState } from "react";
const usePartState = function usePartState(initial) {
    let [state, setState] = useState(initial);
    const setPartState = (partState) => {
        setState({
            ...state,
            ...partState
        });
    };
    return [state, setPartState];
};
export default function Demo() {
    let [state, setState] = usePartState({
        x: 10,
        y: 20
    });
    return <div>
        <span>{state.x}</span>
          
        <span>{state.y}</span>
        <button onClick={() => {
            setState({
                x: state.x + 1
            });
        }}>处理x</button>
    </div>;
};