react useState

useState

useState is a hook function that comes with react, and its function is to declare state variables.
Declaration method:

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

use

<div>{
    
    count}</div>

Change value

setCount(i) // 调用setCount方法参数是想要修改的值

Note:
React Hooks cannot appear in the conditional judgment statement, because it must have exactly the same rendering order.