当设置状态 B 的状态时，React 钩子获取状态 A 的先前状态

Question

For example, if I have two pieces of state:

const [a, setA] = useState(0);
const [b, setB] = useState(0);

And I want to update b using the previous state of both a and b, is there a way to do it without grouping them in an object?

It seems that you can only update the state using the previous state of the same piece of state, like so:

setB(b => b + 1)

Answer 1

you can use hook useCallback and add in dependencies variable a

const setVariable = useCallback(() => {
    setB(b => b + a)
}, [a]);

Answer 2

最近才意识到这里最好的解决方案是使用useReducer钩子。