React Hook "useEffect" is called conditionally. React Hooks must be called in the exact same order in every component render. Did you accidentally call a React Hook after an early return? code example

Example: React Hook "useState" is called in function "app" which is neither a React function component or a custom React Hook function react-hooks/rules-of-hooks

//Try to capitalize 'app' like
const App = props => {...}

export default App;