docs: Missing localStorage.removeItem in persistentStorage example ("Connect to state with URL Chapter")?

[jianchoi02]

Hi!, I'm currently learning Zustand and going through the docs.

While reading the "Connect to state with URL" guide, I noticed a potential omission in the persistentStorage custom storage example.

The example uses localStorage as a fallback in both getItem and setItem. However, the removeItem method only clears the URL search parameters:

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

const getUrlSearch = () => {
  return window.location.search.slice(1)
}

const persistentStorage: StateStorage = {
  getItem: (key): string => {
    // Check URL first
    if (getUrlSearch()) {
      const searchParams = new URLSearchParams(getUrlSearch())
      const storedValue = searchParams.get(key)
      return JSON.parse(storedValue as string)
    } else {
      // Otherwise, we should load from localstorage or alternative storage
      return JSON.parse(localStorage.getItem(key) as string)
    }
  },
  setItem: (key, newValue): void => {
    // Check if query params exist at all, can remove check if always want to set URL
    if (getUrlSearch()) {
      const searchParams = new URLSearchParams(getUrlSearch())
      searchParams.set(key, JSON.stringify(newValue))
      window.history.replaceState(null, '', `?${searchParams.toString()}`)
    }

    localStorage.setItem(key, JSON.stringify(newValue))
  },
  
  // Here!!
  removeItem: (key): void => {
    const searchParams = new URLSearchParams(getUrlSearch())
    searchParams.delete(key)
    window.location.search = searchParams.toString()
  },
}

Should I add localStorage.removeItem(key) to this function to keep it consistent?

removeItem: (key): void => {
    const searchParams = new URLSearchParams(getUrlSearch())
    searchParams.delete(key)
    window.location.search = searchParams.toString()
    
    // 👇 Proposed addition
    localStorage.removeItem(key)
  },

[dai-shi]

cc @dbritto-dev

[dbritto-dev]

@jianchoi02 yes, we need to keep consistency. btw, I'll update the docs/demos with the missing part, thanks for reporting that.

[jianchoi02]

Thanks for the update!