A simple way to sync between WatermelonDB and Firestore.

Using npm :

$ npm install firemelon

Using yarn :

$ yarn add firemelon

Firemelon works with both @firebase/firestore and @react-native-firebase/firestore

import { syncFireMelon } from 'firemelon';

async () => {
    await syncFireMelon(database, syncObject, firestore, sessionId, timefn());
};

• database : The WatermelonDB database to be synced.

• syncObject : An object in which the synced collections and there options are

const syncObject = {
    // collections to sync
    todos: {
        // (optional)
        excludedFields: ['color', 'userId'],

        // To provide extra filters in queries. (optional)
        customQuery: firestore.collection('todos').where('color', '==', 'red'),
    },

    users: {},
};

• firestore : The Firestore module used in the app.

• sessionId : A unique ID for each session to prevent the function from pulling its own pushed changes.

• timefn() :

  A custom function to provide a date for the sync time. default is new Date().

  This is an example of a more accurate way :

  const timefn = () => firestore.FieldValue.serverTimestamp();