问题
What's the difference between
1
const [state, setState] = useState(0)
setState(state+1)
2
const [state, setState] = useState(0)
setState(...prevState => prevState+1)
回答1:
In the first option, based on the documentation:
The
setStatefunction is used to update the state. It accepts a new state value and enqueues a re-render of the component.
In the second option, called functional update:
If the new state is computed using the previous state, you can pass a function to
setState. The function will receive the previous value, and return an updated value.
So basically if you'd like to be sure your state will be updated based on the previous state, you need to use the second option.
Read further in the official documentation of useState.
I hope this clarifies!
来源：https://stackoverflow.com/questions/63058656/react-hook-setstate-usage