getDerivedStateFromProps

getDerivedStateFromProps is a static method in React class components. It is called before the render method, both for the initial mount and for subsequent updates. Its primary purpose is to update the component's state in response to changes in its props. This method receives two arguments: the current props and the current state. It should return an object to update the state, or null if no state update is needed.

This lifecycle method is useful for deriving state from props. For example, if a component needs to display a value that is computed from a prop, and this computed value should also be part of the component's internal state, getDerivedStateFromProps can be used. It ensures that the state is always synchronized with the props.

It is important to note that getDerivedStateFromProps should not have side effects. It is solely for calculating and returning a state update. If you need to perform side effects based on prop changes, such as fetching data, you should use componentDidUpdate. This method is invoked after initial render and before subsequent renders. It's a replacement for the deprecated componentWillReceiveProps method. Developers should be mindful of its use to avoid unnecessary state updates and potential performance issues.