How Does React's `setState` Work, and Why Doesn't It Immediately Update the State?

Understanding State Updates in React

React's setState method is a powerful tool for updating the state of a component. However, it can be surprising to discover that calling setState does not immediately mutate the component's state.

This behavior is explained by React's state management system. When setState is called, it schedules a state transition, rather than immediately updating the state. This allows React to potentially batch state updates and improve performance.

As a result, when you attempt to access the state within the handleChange callback, you may see the original value rather than the newly set value. This is because the state update has not yet been applied.

To resolve this issue, you can pass a callback function to setState. This function will be executed after the state update has been applied, allowing you to access the updated state:

this.setState({value: event.target.value}, function () {
    console.log(this.state.value);
});

By following this approach, you can ensure that you always have access to the latest state value after calling setState.

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