Strange behavior of React hooks: delayed data update

Question

Strange behavior: I expect that the first and the second console.log display a different result, but they display the same result and the value is changed only on the next c

Answer 1

The state update is asynchronous so if you are using Hooks you can use useEffect to be notified after an update.

Here is an example:

https://codesandbox.io/s/wxy342m6l

If you are using setState of a React component, you can use the callback

this.setState((state) => ({count: !state.count}), () => console.log('Updated', this.state.count));

Remember to use the callback to update state if you need a state value.