firebase-redux

Utility functions to connect your Firebase realtime database with a Redux store. This library was written to accompany the Medium article: https://medium.com/@aakashns/575f8294332d

It provides utility functions linkStoreWithPath, linkStoreWithChildren and linkStoreWithDb to set up two-way bindings between portions of the Firebase realtime database and a Redux store.

Installation

Install using npm or yarn:

npm install firebase-redux --save

or

yarn add firebase-redux

Usage

linkStoreWithPath(path, actionCreator, selector)

Set up a two way binding between the realtime database and the Redux store. path specifies the location in the database that is bound, and actionCreator and selector specify how the Redux store should be written to and read from.

Example

import { linkStoreWithPath } from 'firebase-redux';

// The database path you want to bind with
const messagePath = '/message'

// Action to dispatch when the value in the database changes
const messageActionCreator = (message) => ({
  type: 'SET_MESSAGE',
  payload: message
});

// Portion of the state that should be written to the database
const messageSelector = (state) => state.message;

// Create a function to bind '/message' in the database
// with 'state.message' in the Redux store
const linkMessage = linkStoreWithPath(
  messagePath, 
  messageActionCreator, 
  messageSelector
);

// Invoke anywhere in the code to set up the binding
const unlink = linkMessage(firebase.database(), store);

// Invoke unlink to remove the binding
unlink();

linkStoreWithDb(fromDb, fromStore)(database, store)

Set up a custom binding between a Firebase realtime datbase instance and a Redux store. linkStoreWithPath uses linkStoreWithDb internally.

Example

import { linkStoreWithDb } from 'firebase-redux';

// Set up a two way binding between '/message' in the 
// database and 'store.state' in the Redux store
const linkMessage = (db, store) => {
  // Keep track of the previous state
  let previous = store.getState();
  
  // Whether or not to write to the database
  let mustWrite = true;

  const fromDb = (db, dispatch) => {
    const listener = db.ref('/message').on("value", snap => {
      if (snap.val()) {
        // Dont't write the same value back to the database 
        mustWrite = false;
        
        // Update the redux store
        dispatch({
          type: 'SET_MESSAGE',
          payload: snap.val()
        });
        
        // Update is done. Other changes should be written to database
        mustWrite = true;
      }
    });
    
    // Return a method to stop listening for database changes
    return () => db.ref(path).off("value", listener);
  };

  const fromStore = (state, db) => {
    // Get the portion of the state we care about
    const portion = state.message;
    
    // Check if we need to write to the database
    if (mustWrite && portion !== previous) {
      // Write to the datbase
      db.ref(path).set(portion);
    }
    
    // Update the previous state
    previous = portion;
  };

  // Use linkStoreWithDb to tie it all together.
  return linkStoreWithDb(fromDb, fromStore)(db, store);
};

// Invoke anywhere in the code to set up the binding
const unlink = linkMessage(firebase.database(), store);

// Invoke unlink to remove the binding
unlink();