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import { useState, useEffect } from 'react'
export function usePersistantState<V>(
storageKey: string,
defaultValue: V,
options: {
storage?: Storage
} = {},
): [V, (v: V | ((v: V) => V)) => void] {
const storage = getStorage<V | undefined>(storageKey, options.storage ?? localStorage)
const storageValue = storage.get()
const calculatedDefaultValue = storageValue !== undefined ? storageValue : defaultValue
const calculatedDefaultValueObject =
storageValue != null &&
typeof storageValue === 'object' &&
Array.isArray(storageValue) === false
? { ...defaultValue, ...storageValue }
: calculatedDefaultValue
if (calculatedDefaultValueObject !== storageValue) {
storage.update(calculatedDefaultValueObject)
}
const [value, setValue] = useState<V>(calculatedDefaultValueObject)
// change state gracefully when changing the storageKey
useEffect(() => {
if (value !== calculatedDefaultValueObject) {
setValue(calculatedDefaultValueObject)
}
}, [storageKey])
const set = (newValueOrFn: V | ((v: V) => V)) => {
if (newValueOrFn instanceof Function) {
setValue((oldValue) => {
const newValue = newValueOrFn(oldValue)
storage.update(newValue)
return newValue
})
return
}
setValue(newValueOrFn)
storage.update(newValueOrFn)
}
return [value, set]
}
export function getStorage<T>(key: string, storage: Storage) {
return {
get(): T | undefined {
const value = storage.getItem(key)
if (value && value !== 'undefined') {
return JSON.parse(value)
}
return undefined
},
update(updatedState: T) {
storage.setItem(key, JSON.stringify(updatedState))
},
remove() {
storage.removeItem(key)
},
}
}
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