Simple wrapper for local and session storage

wrapStorage.js

/**
 * Simple wrapper for localStorage and sessionStorage,
 * that takes care of data initialization, serialization and deserialization,
 * so you can work with simple JSON-compatible values.
 */
function wrapStorage(storage, initialData = {}) {
  const publicAPI = {
    get size() {
      return storage.length
    },

    keys() {
      return Array.from({ length: this.size }, (_, i) => storage.key(i))
    },

    get(key) {
      const item = storage.getItem(key)
      return item === null ? undefined : JSON.parse(item)
    },

    getAll() {
      return Object.fromEntries(this.keys().map((key) => [key, this.get(key)]))
    },

    set(key, value) {
      storage.setItem(key, JSON.stringify(value))
    },

    remove: storage.removeItem.bind(storage),
    clear: storage.clear.bind(storage),
  }

  for (const [key, value] of Object.entries(initialData)) {
    if (storage.getItem(key) === null) {
      publicAPI.set(key, value)
    }
  }

  return publicAPI
}