atomWithLocation initVaule is not sync

[WeiShengv99]

https://stackblitz.com/edit/github-3vpjew?file=src%2FApp.tsx

• About page has url search params, and i use atomWithLocation to get it
• Other pages dont use atomWithLocation
• enter Home page first is required , then go to About page
  
  

  jotai-location/src/atomWithLocation.ts

  Lines 86 to 97 in 8e7194d

  	baseAtom.onMount = (set) => {
  	const callback = () => set(getL());
  	const unsub = sub(callback);
  	callback();
  	return unsub;
  	};
  	const derivedAtom = atom(
  	(get) => get(baseAtom),
  	(get, set, arg: SetStateAction<T>, atomOptions: AtomOptions<T> = {}) => {
  	set(baseAtom, arg);
  	appL(get(baseAtom), { ...options, ...atomOptions });
  	},

maybe we can return getL() when baseAtom not mount. not just get(baseAtom

[dai-shi]

Thanks for reporting.
While it seems like a bug, it's also working as design.
I wonder if it should be fixed. If we return getL(), it may break compatibility with Concurrent React. But, I'm not very sure.

Let's see if @Flirre has an opinion.

[Flirre]

I'll try to take a proper look at it during the weekend 👀

[Flirre]

I won't have time to investigate this. On a high level it seems like a nice fix, but I'm not sure either about Concurrent React. Could that be checked with some tests?

[dai-shi]

@Flirre Thanks for the note. It's too hard to test actually.

@WeiShengv99 If I understand correctly, the issue can be hidden from the user. Let me know if you have a real issue other than performance problem or unexpected internal behavior.

If anyone is interested in this issue, feel free to jump in.

[WeiShengv99]

the issue can be hidden from the user.

@dai-shi @Flirre Thank you for your work.
I dont have other issue about performance problem or unexpected internal behavior.

Yes,users can add an extra isInit state in their projects to delay read atom state, Actually, that's what I did

const innerLocationAtom = atomWithLocation({
  replace: true,
});
const isInitAtom = atom(false);
const locationAtom = ((get) => get(innerLocationAtom),(_get, set, update: boolean) => {
    set(isInitAtom, update);
  },)
locationAtom.onMount = (setAtom) => {
  setAtom(true);
  return () => {
    setAtom(false);
  };
}

If return getL() may break compatibility with Concurrent React, this issue should be handled by the users themselves.