In React, updating the state directly is discouraged for several reasons:
React's Re-rendering Process: React's state management is designed to be predictable and efficient. When you update the state directly, such as this.state.value = 'new value', React does not recognize this change immediately. This is because React batches state updates and determines when to re-render the component based on its own internal mechanisms. Direct modifications bypass this mechanism, so the component does not re-render, and the UI does not update to reflect the change[1][4][5][6].
Asynchronous Nature of setState(): The setState() method in React is asynchronous. It schedules updates to the component's state and informs React that this component and its children need to be re-rendered with the updated state. This approach ensures that React can optimize the updates and avoid unnecessary re-renders. When you modify the state directly, you lose the benefits of React's asynchronous state updates, which can lead to performance issues[1][2][3][4].
Maintaining State Integrity: Directly mutating the state can lead to subtle bugs, especially in complex applications where the state might be used in multiple places or when the next state depends on the previous one. Using setState() ensures that changes to the state are queued and applied at an appropriate time, maintaining the integrity of state across all uses within the application[1][4][6].
