Demo

/**
 * Sample React Native App
 * https://github.com/facebook/react-native
 *
 * @format
 * @flow strict-local
 */
import '@babel/polyfill';
import React, {useEffect, useState} from 'react';
import {
  SafeAreaView,
  StyleSheet,
  ScrollView,
  View,
  Text,
  StatusBar,
} from 'react-native';
import {decode, encode} from 'base-64';
import {
  Header,
  LearnMoreLinks,
  Colors,
  DebugInstructions,
  ReloadInstructions,
} from 'react-native/Libraries/NewAppScreen';
import SQLiteAdapterFactory from 'pouchdb-adapter-react-native-sqlite';
import SQLite from 'react-native-sqlite-2';

import {addRxPlugin, createRxDatabase} from 'rxdb';
let localdb = null;
let sub = null;

if (!global.btoa) {
  global.btoa = encode;
}

if (!global.atob) {
  global.atob = decode;
}

process.browser = true;

const SQLiteAdapter = SQLiteAdapterFactory(SQLite);
addRxPlugin(SQLiteAdapter);
addRxPlugin(require('pouchdb-adapter-http'));

const schema = {
  title: 'Anonymous chat schema',
  description: 'Database schema for an anonymous chat',
  version: 0,
  type: 'object',
  properties: {
    count: {
      type: 'number',
      default: 0,
    },
  },
};

const App = () => {
  const [count, setCount] = useState(0);

  useEffect(() => {
    console.log("App -> setCount", setCount)
    createRxDatabase({
      name: 'heroesdb',
      adapter: 'react-native-sqlite', // the name of your adapter
      multiInstance: false,
      ignoreDuplicate: true,
    })
      .then((db) => {
        localdb = db;
        return localdb.collection({
          name: 'count',
          schema,
        });
      })
      .then(() => {
        return localdb.count.findOne().exec();
      })
      .then((result) => {
        if (result === null) {
          localdb.count.insert({});
        }

        sub = localdb.count.findOne().$.subscribe(function(raw) {

        setTimeout(async () => {
          const changeFunction = (oldData) => {
            oldData.count = oldData.count + 1;
            return oldData;
        }
        await raw.atomicUpdate(changeFunction);
        }, 2000)
          setCount(raw.count);
        })
      });
    return () => {
      sub.unsubscribe();
    }
  }, []);
  return (
    <>
      <StatusBar barStyle="dark-content" />
      <SafeAreaView>
        <Text>Count: {count}</Text>
      </SafeAreaView>
    </>
  );
};

const styles = StyleSheet.create({
  scrollView: {
    backgroundColor: Colors.lighter,
  },
  engine: {
    position: 'absolute',
    right: 0,
  },
  body: {
    backgroundColor: Colors.white,
  },
  sectionContainer: {
    marginTop: 32,
    paddingHorizontal: 24,
  },
  sectionTitle: {
    fontSize: 24,
    fontWeight: '600',
    color: Colors.black,
  },
  sectionDescription: {
    marginTop: 8,
    fontSize: 18,
    fontWeight: '400',
    color: Colors.dark,
  },
  highlight: {
    fontWeight: '700',
  },
  footer: {
    color: Colors.dark,
    fontSize: 12,
    fontWeight: '600',
    padding: 4,
    paddingRight: 12,
    textAlign: 'right',
  },
});

export default App;