useLocalStorage without 'or undefined'

[rromikas]

[isEasyToUse, setIsEasyToUse] = useLocalStorage("easyToUse", false)

Why value is boolean | undefined?

[rubickecho]

i think you will provide more infomation

[giannif]

I'm surprised by this too, I expected the following to return the same types for the state and the state dispatcher

const [localStorageArray, setLocalStorageArray] = useLocalStorage<string[]>('some-array', [])
const [stateArray, setStateArray] = useState<string[]>([])

localStorageArray isstring[] | undefined
setLocalStorageArray is Dispatch<SetStateAction<string[] | undefined>>

stateArray is string[]
setStateArray is Dispatch<SetStateAction<string[]>>

I would expect this if the initialValue isn't set, but we are passing in an []