Possible typo in the docs connect state to URL example

[AmitaiRosenbaum]

Bug Description

In the docs, there is the following example for creating your own hash storage

import { create } from 'zustand'
import { persist, StateStorage, createJSONStorage } from 'zustand/middleware'

const hashStorage: StateStorage = {
  getItem: (key): string => {
    const searchParams = new URLSearchParams(location.hash.slice(1))
    const storedValue = searchParams.get(key) ?? ''
    return JSON.parse(storedValue)
  },
  setItem: (key, newValue): void => {
    const searchParams = new URLSearchParams(location.hash.slice(1))
    searchParams.set(key, JSON.stringify(newValue))
    location.hash = searchParams.toString()
  },
  removeItem: (key): void => {
    const searchParams = new URLSearchParams(location.hash.slice(1))
    searchParams.delete(key)
    location.hash = searchParams.toString()
  },
}

However, in zustand/esm/middleware/persist.d.mts, the following interface is declared for StateStorage.

import type { StateCreator, StoreMutatorIdentifier } from 'zustand/vanilla';
export interface StateStorage {
    getItem: (name: string) => string | null | Promise<string | null>;
    setItem: (name: string, value: string) => unknown | Promise<unknown>;
    removeItem: (name: string) => unknown | Promise<unknown>;
}

Unless I have missed something, it looks like there is an inconsistency between the declared return type, and the return type given in the example docs.

E.g. the get should return string | null but returns the output of JSON.parse.

Reproduction Link

https://zustand.docs.pmnd.rs/learn/guides/connect-to-state-with-url-hash

[dai-shi]

@dbritto-dev Can you take a look?

[dbritto-dev]

@dai-shi sure

[dbritto-dev]

@AmitaiRosenbaum @AmitaiRosenbaum there's no typo, in this scenario that JSON.parse return a string

[AmitaiRosenbaum]

That's true for this particular case at runtime, but JSON.parse does not always return a string. So you would not be able to run a NextJS typescript production server using this code because you would get a type error at build time.

[dbritto-dev]

@AmitaiRosenbaum I don't get it, why you would use something like this with Nextjs? You need to understand when to use something and that's on userland.