react-native-mmkv/lib/hooks/useMMKVListener.js

⚡️ The fastest key/value storage for React Native.

import { useEffect, useRef } from 'react';
import { getDefaultMMKVInstance } from '../createMMKV/getDefaultMMKVInstance';
/**
 * Listen for changes in the given MMKV storage instance.
 * If no instance is passed, the default instance will be used.
 * @param valueChangedListener The function to call whenever a value inside the storage instance changes
 * @param instance The instance to listen to changes to (or the default instance)
 *
 * @example
 * ```ts
 * useMMKVListener((key) => {
 *   console.log(`Value for "${key}" changed!`)
 * })
 * ```
 */
export function useMMKVListener(valueChangedListener, instance) {
    const ref = useRef(valueChangedListener);
    ref.current = valueChangedListener;
    const mmkv = instance ?? getDefaultMMKVInstance();
    useEffect(() => {
        const listener = mmkv.addOnValueChangedListener((changedKey) => {
            ref.current(changedKey);
        });
        return () => listener.remove();
    }, [mmkv]);
}