實現useState

js實現一個useState，簡單的原理就是賦值然后更新渲染，大概偽代碼如下：

   function useState(initValue) {let value = initValue;function setValue(v) {if (typeof v === "function") {value = v(initValue);} else {value = v;}// 更新布局renderWithMyHook();}return [value, setValue];}function renderWithMyHook() {ReactDOM.render(<App />, document.getElementById("root"));}