Why should we not update the state directly?

In React, it’s advised not to update the state directly using the this.state syntax or by modifying the state object directly. Instead, you should use the setState method provided by React. Here are some reasons why:

• Asynchronous State Updates: State updates in React are asynchronous. When you use setState, React may batch multiple state updates for performance reasons. If you modify the state directly, you might not get the expected result since React may not have processed the update yet.
• State Immutability: React relies on the concept of immutability for state updates. Directly modifying the state object can lead to unexpected behavior and make it difficult for React to optimize and reconcile the virtual DOM.
• Component Re-rendering: When you use setState, React is aware of the state change, triggers a re-render, and efficiently updates the DOM. If you modify the state directly, React may not detect the change, and your component might not re-render as expected.
• Potential Bugs: Modifying the state directly can introduce subtle bugs that are hard to track down. React provides a controlled way to manage state updates through the setState function, and bypassing it may lead to unpredictable behavior.

Example: Here’s an example to illustrate the issue:

Javascript

// Incorrect way: Modifying state directly
this.state.counter = this.state.counter + 1;

// Correct way: Using setState
this.setState(
    (prevState) =>
    (
        {
            counter: prevState.counter + 1
        }
    ));

In the correct example, the setState function ensures that the state update is performed in a predictable and asynchronous manner. It also follows the principle of immutability by creating a new state object based on the previous state.

By adhering to React’s guidelines for state management, you can write more predictable, maintainable, and bug-free components.