react-native-mmkv
react-native-mmkv copied to clipboard
mrousavy
Settings a `false` value is equivalent to delete
When settings a value which is false, the next getBoolean operation will return undefined.
I can confirm this happens.
Whenever we try to set the value to false, next get operation will return undefined.
"react-native-mmkv": "2.5.1", "react-native": "0.65.2".
Tested on Android.
Hmm, this is weird, maybe there is some casting going on? Can this be reproduced in the example app?
I think I found the problem in my case.
I was using mmkv like this.
export default function useStorage<T>(storageKey: string, initialValue: T) {
const [storedValue, setStoredValue] = useState<T>(() => {
const storedValue = storage.getString(storageKey)
return storedValue ? JSON.parse(storedValue) : initialValue
})
const setValue = useCallback(
(value: T) => {
setStoredValue(value)
storage.set(storageKey, JSON.stringify(value))
},
[storageKey]
)
return { value: storedValue, setValue }
}
I was stringifying all the values while setting and parsing them while getting. However, when I set -1 as a string "-1", it was deleting the value and I was getting undefined on the next call to get.
Changing it like this fixed it for me.
export default function useStorage<T>(storageKey: string, initialValue: T) {
const [storedValue, setStoredValue] = useState<T>(() => {
if (typeof initialValue === 'number') {
return storage.getNumber(storageKey) ?? initialValue
}
if (typeof initialValue === 'boolean') {
return storage.getBoolean(storageKey) ?? initialValue
}
const value = storage.getString(storageKey)
return value ? JSON.parse(value) : initialValue
})
const setValue = useCallback(
(value: T) => {
if (typeof value === 'number' || typeof value === 'boolean') {
storage.set(storageKey, value)
setStoredValue(value)
return
}
storage.set(storageKey, JSON.stringify(value))
setStoredValue(value)
},
[storageKey]
)
return { value: storedValue, setValue }
}
Hey! Does this problem still persist? Is the code you posted the reproduceable example?