code: function get (key, def) {
    if (Array.isArray(key)) {
      return AsyncStorage.multiGet(key)
        .then((values) => values.map(([_, value]) => {
          return useDefault(def, value) ? def : parse(value)
        }))
        .then(results => Promise.all(results))
    }
  
    return AsyncStorage.getItem(key).then(value => useDefault(def, value) ? def : parse(value))
  }
docs: Retreive value from AsyncStorage based on key.
  Wrapper around getItem & multiGet.
  
  @param {String, Array} key Key to lookup
  @param {Any} def Default value
  
  @returns {Promise} value of key
  
  @example
  storage.get('foo').then(console.log).catch(console.error)