尽量让 react 帮你处理一切。


```tsx
export const Main = (props)=>{
let [count, setCount] = React.useState<number>(0);
const onWheel = (ev: WheelEvent) => {
ev.preventDefault();
setCount(count + Math.floor(Math.abs(ev.deltaY / 5)));
};
let divs = new Array<number>(25000)
.fill(0)
.map((v, i) => <div key={i + count}>{i + count}</div>);
return <div onWheel={onWheel}>{divs}</div>;
}
```