minnan-collect-web/src/composeable/MemorizeVar.ts

import { onMounted, ref, watch } from "vue";

export function memorizeVar<T>(key: string, defaultValue: T) {
  const variable = ref<T>(defaultValue);

  onMounted(() => {
    const v = localStorage.getItem(key);
    if (v)
      variable.value = JSON.parse(v);
  });
  watch(variable, (newValue) => {
    localStorage.setItem(key, JSON.stringify(newValue));
  });

  return { 
    variable
  };
}