如何在React中使用钩子强制组件重新呈现？

Question

   import { useState } from 'react';

   function Example() {
       const [count, setCount] = useState(0);

       return (
           <div>
               <p>You clicked {count} times</p>
               <button onClick={() => setCount(count + 1)}>
                  Click me
               </button>
          </div>
        );
     }

    class Test extends Component{
        constructor(props){
             super(props);
             this.state = {
                 count:0,
                 count2: 100
             }
             this.setCount = this.setCount.bind(this);//how can I do this with hooks in functional component 
        }
        setCount(){
              let count = this.state.count;
                   count = count+1;
              let count2 = this.state.count2;
                   count2 = count2+1;
              this.setState({count});
              this.forceUpdate();
              //before below setState the component will re-render immediately when this.forceUpdate() is called
              this.setState({count2: count
        }

        render(){
              return (<div>
                   <span>Count: {this.state.count}></span>. 
                   <button onClick={this.setCount}></button>
                 </div>
        }
 }

但我的问题是我如何强制上面的功能组件重新呈现立即与钩子？

Answer 1

这对于USTEST或UserEducer是可能的，因为USTEST在内部使用UserEducer:

const [, updateState] = React.useState();
const forceUpdate = React.useCallback(() => updateState({}), []);

forceupdate不打算在正常情况下使用，只用于测试或其他未完成的情况。这种情况可以用更传统的方式来解决。

SetCount是使用不当的ForceUpdate的一个示例，SetState由于性能原因是异步的，不应该仅仅因为状态更新没有正确执行而强制同步。如果一个状态依赖于先前设置的状态,则应使用updater函数完成此操作,

如果需要基于以前的状态设置状态，请阅读下面的updater参数。

<...>

更新器功能接收到的状态和道具都保证是最新的。更新程序的输出与状态略有合并。

setCount(){
  this.setState(({count}) => ({ count: count + 1 }));
  this.setState(({count2}) => ({ count2: count + 1 }));
  this.setState(({count}) => ({ count2: count + 1 }));
}

   const [state, setState] = useState({ count: 0, count2: 100 });

   const setCount = useCallback(() => {
     setState(({count}) => ({ count: count + 1 }));
     setState(({count2}) => ({ count2: count + 1 }));
     setState(({count}) => ({ count2: count + 1 }));
   }, []);