react-native-async-storage-listener

A wrapper around React Native's AsyncStorage with a listener. Multiple Channels are supported. Can be used where redux is not available.

Usage

import StorageListener from react-native-async-storage-listener

//test classes for subscribe demonstration
class TestClassA {
    callback = (text:string)=> {
        console.log('CALLBACK CALLED FOR INSTANCE OF CLASS A:', text)
    }
    callbackSecond = (text:string)=> {
        console.log('SECOND CALLBACK CALLED FOR INSTANCE OF CLASS A:', text)
    }
}

class TestClassB {
    callback = (text:string)=> {
        console.log('CALLBACK CALLED FOR INSTANCE OF CLASS B:', text)
    }
}

// demo
const a = new TestClassA();
const b = new TestClassB();

//initiating channels by setting values
StorageListener.setItem("test value 1", "CHANNEL 1");
StorageListener.setItem("test value 2", "CHANNEL 2");

//get available channels for subscription
const channels = StorageListener.getChannels()


const response = StorageListener.addSubscriber(a.callback, channels[0])
// console.log(response)
// {  success: true, message: 'subscribed to channel', subscriber_id: 'a13151d6-1336-4096-933c-eb8e12cd0b10'}
// subscriber_id is required to remove the subscription 
 
StorageListener.addSubscriber(b.callback, channels[0])
StorageListener.addSubscriber(a.callbackSecond, channels[1])
StorageListener.setItem("test value A", "CHANNEL 1");
StorageListener.setItem("test value A", "CHANNEL 2");
//callbacks will be called for any update

const remove = StorageListener.removeSubscriber(subscriber_id);
// console.log(remove)
// returns true if subscriber_id is a valid id

StorageListener.removeAllSubscribers();
// removes all subscribers

API Reference

setItem

creates new channel or updates the value of an existing channel

parameters

value:string - The value to update with

channelKey:string - new channel key or a existing channel key

returns: void

getItem

get value of an existing channel

parameters

channelKey:string - existing channel key

returns: string

getChannels

get all available existing channels

parameters: none

returns: Array<string>

addSubscriber

add a new subscriber

parameters

callback: (state:string)=>void - callback function with void return

channelKey:string - existing channel key that wish to subscribe

returns: {success: true, message: "subscribed to channel", subscriber_id: key} | {success:false , message: "channel not found. use an existing channel key"}

removeSubscriber

remove a subscriber

parameters

key:string - subscriber_id returned from addSubscriber response

returns: boolean

removeAllSubscribers

remove all subscribers

parameters: none

returns: void