AsyncStorage - Amazon Vega Docs

AsyncStorage is an unencrypted, asynchronous, persistent, key-value storage system that is global to the app. It should be used instead of LocalStorage. It is recommended that you use an abstraction on top of AsyncStorage instead of AsyncStorage directly for anything more than light usage since it operates globally.

Installation

Importing the legacy version of the AsyncStorage library:

import AsyncStorage from '@amazon-devices/react-native-kepler';

Note: AsyncStorage was recently removed from the mainline React Native libraries. We are working on creating a path to use AsyncStorage more idiomatically. Until this is completed, include AsyncStorage in place of the import as follows:

const AsyncStorage = require("@amazon-devices/react-native-kepler/Libraries/Storage/AsyncStorage");

Be aware that this imports AsyncStorage as type any, thus any related code will have relaxed type checking. Persisting data:

_storeData = async () => {
  try {
    await AsyncStorage.setItem(
      '@MySuperStore:key',
      'I like to save it.',
    );
  } catch (error) {
    // Error saving data
  }
};

Fetching data:

_retrieveData = async () => {
  try {
    const value = await AsyncStorage.getItem('TASKS');
    if (value !== null) {
      // We have data!!
      console.log(value);
    }
  } catch (error) {
    // Error retrieving data
  }
};

API reference

getItem()

static getItem(key: string, [callback]: ?(error: ?Error, result: ?string) => void)

Fetches an item for a key and invokes a callback upon completion. Returns a Promise object. Parameters:

Name	Type	Required	Description
key	string	Yes	Key of the item to fetch.
callback	`?(error: ?Error, result: ?string) => void`	No	Function that will be called with a result if found or any error.

setItem()

static setItem(key: string, value: string, [callback]: ?(error: ?Error) => void)

Sets the value for a key and invokes a callback upon completion. Returns a Promise object. Parameters:

Name	Type	Required	Description
key	string	Yes	Key of the item to set.
value	string	Yes	Value to set for the `key`.
callback	`?(error: ?Error) => void`	No	Function that will be called with any error.

removeItem()

static removeItem(key: string, [callback]: ?(error: ?Error) => void)

Removes an item for a key and invokes a callback upon completion. Returns a Promise object. Parameters:

Name	Type	Required	Description
key	string	Yes	Key of the item to remove.
callback	`?(error: ?Error) => void`	No	Function that will be called with any error.

clear()

static clear([callback]: ?(error: ?Error) => void)

Erases all AsyncStorage for all clients, libraries, etc. You probably don’t want to call this; use removeItem or multiRemove to clear only your app’s keys. Returns a Promise object. Parameters:

Name	Type	Required	Description
callback	`?(error: ?Error) => void`	No	Function that will be called with any error.

multiGet()

static multiGet(keys: Array<string>, [callback]: ?(errors: ?Array<Error>, result: ?Array<Array<string>>) => void)

This allows you to batch the fetching of items given an array of key inputs. Your callback will be invoked with an array of corresponding key-value pairs found:

multiGet(['k1', 'k2'], cb) -> cb([['k1', 'val1'], ['k2', 'val2']])

The method returns a Promise object. Parameters:

Name	Type	Required	Description
keys	`Array<string>`	Yes	Array of key for the items to get.
callback	`?(errors: ?Array<Error>, result: ?Array<Array<string>>) => void`	No	Function that will be called with a key-value array of the results, plus an array of any key-specific errors found.

Example:

AsyncStorage.getAllKeys((err, keys) => {
  AsyncStorage.multiGet(keys, (err, stores) => {
    stores.map((result, i, store) => {
      // get at each store's key/value so you can work with it
      let key = store[i][0];
      let value = store[i][1];
    });
  });
});

multiSet()

static multiSet(keyValuePairs: Array<Array<string>>, [callback]: ?(errors: ?Array<Error>) => void)

Use this as a batch operation for storing multiple key-value pairs. When the operation completes you’ll get a single callback with any errors:

multiSet([['k1', 'val1'], ['k2', 'val2']], cb);

The method returns a Promise object. Parameters:

Name	Type	Required	Description
keyValuePairs	`Array<Array<string>>`	Yes	Array of key-value array for the items to set.
callback	`?(errors: ?Array<Error>) => void`	No	Function that will be called with an array of any key-specific errors found.

multiRemove()

static multiRemove(keys: Array<string>, [callback]: ?(errors: ?Array<Error>) => void)

Call this to batch the deletion of all keys in the keys array. Returns a Promise object. Parameters:

Name	Type	Required	Description
keys	`Array<string>`	Yes	Array of key for the items to delete.
callback	`?(errors: ?Array<Error>) => void`	No	Function that will be called an array of any key-specific errors found.

Example:

let keys = ['k1', 'k2'];
AsyncStorage.multiRemove(keys, err => {
  // keys k1 & k2 removed, if they existed
  // do most stuff after removal (if you want)
});

​Installation

​API reference

​getItem()

​setItem()

​removeItem()

​clear()

​multiGet()

​multiSet()

​multiRemove()