class JsStorage {
  constructor() {
    this.db = {}
  }

  get(key) {
    return this.db[key]
  }

  get_or_element(key, defaultElement) {
    const element = this.db[key]
    if (element === undefined) {
      return defaultElement
    } else {
      return element
    }
  }

  put(key, value) {
    if (key === undefined || value === undefined) {
      throw Error('key or value is undefined')
    }
    this.db[key] = value
  }

  del(key) {
    delete this.db[key]
  }

  put_batch(key_values) {
    key_values.forEach((element) => {
      this.db[element.key] = element.value
    })
  }
}

module.exports = JsStorage