I have App component which returns only a react component called Home. Inside App component, I have a useEffect which has no dependancy, in order to trigger any changes. I expect the App useEffect to rerender when something changes in the home component, but this doesnt happen. Doesnt react support such thing?

CodePudding user response：

This is not supported out of the box. The child will rerender when parent rerenders but not the other way around.

If every parent rerenders when a child rerender, then even a tiny button state change will cause the whole tree to rerender.

You have callbacks that can help you get around this. The child should be passed a callback function as a prop. Inside this callback function body the parent state will be updated. So now when this function runs (from within the child). The parent also rerenders.