For those wanting to share state received from a page's getServerSideProps
function to global components in pages/_app.tsx
, I've pieced this solution together.
- Create a shared
getServerSideProps
function to include on all pages
- Create a shared
useSetUserStorage
custom hook to include on all pages
- Listen for
localStorage
changes with custom event listener in global component (e.g. GlobalNav
)
It's a work around, but is working for me so far (note that it includes some specifics to my use of getServerSideProps
function).
It's a fair amount of code but hopefully this helps someone:
// src/pages/_app.tsx
import type { AppProps } from "next/app";
import GlobalNav from "../components/GlobalNav";
function MyApp({ Component, pageProps: { session, ...pageProps } }: AppProps) {
return (
<>
<GlobalNav /> // <— your global component
<Component {...pageProps} />
</>
);
}
export default MyApp;
// src/utils/getServerSideProps.ts
import { ppinit, ppsession, sess } from "../authMiddleware";
import nc from "next-connect";
import { NextApiRequest, NextApiResponse } from "next";
import { User } from "../types/types";
interface ExtendedReq extends NextApiRequest {
user: User;
}
interface ServerProps {
req: ExtendedReq;
res: NextApiResponse;
}
interface ServerPropsReturn {
user?: User;
}
//
// Here we use middleware to augment the `req` with the user from passport.js
// to pass to the page
// src: https://github.com/hoangvvo/next-connect/tree/21c9c73fe3746e66033fd51e2aa01d479e267ad6#runreq-res
//
const getServerSideProps = async ({ req, res }: ServerProps) => {
// ADD YOUR CUSTOM `getServerSideProps` code here
const middleware = nc()
.use(sess, ppinit, ppsession)
.get((req: Express.Request, res: NextApiResponse, next) => {
next();
});
try {
await middleware.run(req, res);
} catch (e) {
// handle the error
}
const props: ServerPropsReturn = {};
if (req.user) props.user = req.user;
return { props };
};
export interface Props {
user?: User;
}
export default getServerSideProps;
// src/hooks.ts
import { useEffect } from "react";
import { User } from "./types/types";
export const useSetUserStorage = (user?: User) => {
useEffect(() => {
if (user) {
localStorage.setItem("user", JSON.stringify(user));
} else {
localStorage.removeItem("user");
}
// whether setting or removing the user, dispatch event so that `GlobalNav`
// component (which is above the page implementing this hook in the
// component hierarchy) can be updated to display the user status. we
// can't use `window.addEventListener('storage', handler)` as this only
// works for listening for events from other pages
document.dispatchEvent(new Event("localStorageUserUpdated"));
});
return null;
};
// src/pages/index.tsx (or any page)
import { useSetUserStorage } from "../hooks";
import { Props } from "../utils/getServerSideProps";
export { default as getServerSideProps } from "../utils/getServerSideProps";
export default function Home({ user }: Props) {
useSetUserStorage(user);
return (
<>
<h1>Welcome to my app {user?.username}</h1>
</>
);
}
// src/components/GlobalNav.ts (or another global component)
import { useEffect, useState, MouseEvent } from "react";
import { User } from "../types/types";
const GlobalNav = () => {
const [user, setUser] = useState<User | null>(null);
useEffect(() => {
const handleUserLocalStorage = () => {
const userString = localStorage.getItem("user");
try {
if (userString) {
setUser(JSON.parse(userString));
} else {
setUser(null);
}
} catch (e) {
// handle parse error
}
};
handleUserLocalStorage();
// this component (`GlobalNav`) lives at the application level, above the
// pages, but the pages receive the user object from `getServerSideProps`,
// so this listener listens for when a page tells us the user object has
// changed so we can update the `user` state here.
document.addEventListener(
"localStorageUserUpdated",
handleUserLocalStorage,
false,
);
return () => {
// remove listener if component unmounts
document.removeEventListener(
"localStorageUserUpdated",
handleUserLocalStorage,
);
};
}, []);
return (
<div>
{user?.username}
</div>
);
};
export default GlobalNav;