I have React App consisting of few pages. LandingPage (to be clear, it is really the first page in app flow)is like this:
export const LocalLandingPage = () => {
const { Favorites } = useFavorites();
React.useEffect(() => {
Favorites.manageSupport() && Favorites.showSize();
}, []);
return (...here goes actual content...);
};
const LandingPage = withRouter(wrappedInLinkToSearchHOC(WithSnackBarHOC(LocalLandingPage)));
Here I call hook useFavorites which gathers some methods dealing with a specific subset of local Storage content(and dispatches actions to Redux store as well). The code above return call is checks support for local Storage and tells if some specific items are stored and in what quantity.
The story is that I have realized that if someone enters not the LandingPage but any other page of the app, the code will not be executed and support for localStorage not checked.
Besides, it is really not LandingPage business to deal with storage, so it should be removed anywhere.
My idea was to write HOC and wrap the application. So, here is this HOC (to keep things simple it is initially JS not TS) To make useFavorites work, it had to be a hook, too.
import useFavorites from '../hooks/useFavorites';
const useCheckSupportForLocalStorage = Component => {
const { Favorites } = useFavorites();
// React.useEffect(() => {
Favorites.manageSupport() && Favorites.showSize();
// }, []);
return props => <Component {...props} />;
};
export default useCheckSupportForLocalStorage;
Having it done, I have tried to use it on App like this
function App() {
return (
<Switch>
... here are routes...
</Switch>
);
}
export default useCheckSupportForLocalStorage(App);
It throws an error:
React Hook "useCheckSupportForLocalStorage" cannot be called at the top level.
That is truth, no doubt. So, the next idea was to create a temporary component from all routes.
function Routes() {
const Routes = useCheckSupportForLocalStorage(
<>
<Route exact path={Paths.landing} component={Awaiting(StarWars)} />
...here is the rest or outes...
</>,
);
return <Routes />;
}
export default Routes;
And use it in rewritten App like this
function App() {
return (
<Switch>
<Routes />
</Switch>
);
}
but it throws error
Routes’ cannot be used as a JSX component.
Its return type ‘(props: any) => Element’ is not a valid JSX element.
Type ‘(props: any) => Element’ is missing the following properties from type ‘ReactElement<any, any>’: type, props, key
Forcing useCheckSupportForLocalStorage th have return type of ReactElement doesn’t help, just leads to other error. I have checked few others options as well. What is wrong, how should it be written?
Basically I could stop using useFavorites in this hook, then it would be just a function – but it would be extreme headache.
>Solution :
You say
To make
useFavoriteswork, it had to be a hook, too.
That is not true, since you have it in a component it will work just fine. And my understanding is that you want to wrap your whole app with it, so no need for the HOC. Just use it at the top of your app hierarchy.
something like
import useFavorites from '../hooks/useFavorites';
const CheckSupportForLocalStorage = ({ children }) => {
const { Favorites } = useFavorites();
React.useEffect(() => {
Favorites.manageSupport() && Favorites.showSize();
}, []);
return children;
};
export default CheckSupportForLocalStorage;
and
function App() {
return (
<CheckSupportForLocalStorage>
<Switch>
... here are routes...
</Switch>
</CheckSupportForLocalStorage>
);
}
export default App;