React - setState does not update the value

Question

I am trying to update the state with a localStorage value in DidMount, but it is not updating:

type Props = {
};

type State = {
    id_evaluation: string,
};

c         


        

Answer 1

setState works asynchronously so pass console.log as callback to get updated state.

this.setState({ id_evaluation: '1'}, () => console.log('2- ', this.state.id_evaluation));

when used as your code, console.log('2 - ', this.state.id_evaluation) is printing previous state not the updated state.

Answer 2

this.setState is an async function.

 this.setState({
        id_evaluation: '1',
 }, () => console.log('2 - ', this.state.id_evaluation));

Callback function would solve your problem.

Answer 3

That is because you call console.log before the state has updated. Try this:

this.setState({
  id_evaluation: '1',
}, () => {
  console.log('2 - ', this.state.id_evaluation);
});

See this thread:

Can I execute a function after setState is finished updating?