calendar/src/plugins/persist.js

// Simple Pinia persistence plugin supporting `persist: true` and Map serialization.
export function persistPlugin({ store }) {
  if (!store.$options || !store.$options.persist) return
  const key = `pinia-${store.$id}`
  try {
    const raw = localStorage.getItem(key)
    if (raw) {
      const state = JSON.parse(raw, (k, v) => {
        if (v && v.__map === true && Array.isArray(v.data)) return new Map(v.data)
        return v
      })
      store.$patch(state)
    }
  } catch {}
  store.$subscribe((_mutation, state) => {
    try {
      const json = JSON.stringify(state, (_k, v) => {
        if (v instanceof Map) return { __map: true, data: Array.from(v.entries()) }
        return v
      })
      localStorage.setItem(key, json)
    } catch {}
  })
}