SaaS starter

import { useEffect, useState } from "react";

/** Persist state in localStorage. Safe when storage is unavailable (private mode). */
export function useLocalStorage<T>(key: string, initial: T): [T, (next: T | ((prev: T) => T)) => void] {
  const [value, setValue] = useState<T>(() => {
    try {
      const raw = window.localStorage.getItem(key);
      return raw ? (JSON.parse(raw) as T) : initial;
    } catch {
      return initial;
    }
  });
  useEffect(() => {
    try {
      window.localStorage.setItem(key, JSON.stringify(value));
    } catch {
      // ignore quota / privacy errors
    }
  }, [key, value]);
  return [value, setValue];
}