Accept a function in writeStorage as well as an object/string

[Harley Alexander]

In the basic useState hook, you can access current state when setting the next state like so:setState(prev => !prev)

This is handy when you're using it within a useEffect so you don't need to add the extra dependency.

Would something like this work? I can create a PR if so;

export function writeStorage<TValue>(key: string, value: TValue) {
    try {
       // check for a function, run it with the current value;
       if (typeof value === "function") {
            const existingState = localStorage.getItem(key);
            value = value(existingState);
        }

        localStorage.setItem(key, typeof value === 'object' ? JSON.stringify(value) : `${value}`);
        window.dispatchEvent(new LocalStorageChanged({ key, value }));
    } catch(err) {
       ...
    }
}```

[Amit Solanki]

If you are getting value directly from local storage, you can do the same inside the useEffect without adding any dependency.