code: function get(key, store = getDefaultStore()) {
    let req
    return store[IDBStore]('readonly', store => {
      req = store.get(key)
    }).then(() => req.result)
  }
docs: Get a value based on the provided key.
  @param {string} key The key to use.
  @param {any} store A default value provided by IDB.
  @return {Promise} Promise