关于react.js:react手写useState

let _state=[];let index=0;function myUseState(initialValue) {  int currentIndex=index;    //引入两头变量currentIndex就是为了保留以后操作的下标index。  _state[currentIndex] = _state[currentIndex]===undefined? initialValue:_state[currentIndex];  const setState = (newValue) => {    _state[currentIndex] = newValue;     render();   };  index+=1;// 每次更新完state值后，index值+1  return [_state[currentIndex], setState];}const render = () => {  index=0;    //重要的一步，必须在渲染前后将index值重置为0，不然index会一种减少1  ReactDOM.render(<App />, document.getElementById("root"));};// 应用myUseStateconst App = () => {  const [n, setN] = myUseState(0);  const [m, setM] = myUseState(0);  return (      <div classNam="App">         <p>n:{n}</p>         <button onClick={()=>{setN(n+1)}}>n+1</button>          <p>m:{m}</p>         <button onClick={()=>{setM(m+1)}}>n+1</button>       </div>      );};ReactDOM.render(<App />, document.getElementById("root"));