react-native-firebase/docs/redux.md

Usage with Redux

Although RNFirebase usage requires a React Native environment, it isn't tightly coupled which allows for full flexibility when it comes to integrating with other modules such a react-redux. If you wish to use a Redux library designed for Firebase, we suggest taking a look at react-redux-firebase for implementation with this module.

Standalone integration

Although the following example works for a basic redux setup, it may differ when integrating with other redux middleware. Imagine a simple TODO app, with redux we're able to abstract the Firebase logic out of components which allows for greater testability and maintainability.

?> We use redux-thunk to provide async actions.

Action Creators

// Actions
export const subscribe = () => {
  return (dispatch) => {
    firebase.database().ref('todos').on('value', (snapshot) => {
      const todos = [];
      
      snapshot.forEach((childSnapshot) => {
        todos.push({
          id: childSnapshot.key,
          ...(childSnapshot.val()),
        })
      })
      
      dispatch({
        type: 'TODO_UPDATE',
        todos,
      })
    })
  }
}

// Methods
export const addTodo = text => {
  firebase.database().ref('todos').push({
    text,
    visible: true,
  })
}

export const completeTodo = id => {
  firebase.database().ref(`todos/${id}`).update({
    visible: false,
  })
}

Instead of creating multiple actions which the reducers handle, we instead subscribe to the database ref and on any changes, send a single action for the reducers to handle with the data which is constantly updating.

Reducers

Our reducer now becomes really simple, as we're able to simply update the reducers state with whatever data has been returned from our Firebase subscription.

const todos = (state = {}, action) => {
  switch (action.type) {
    case 'TODO_UPDATE':
      return { ...action.todos };
  }
  
  return state;
}

export default todos;

Component

We can now easily subscribe to the todos in redux state and get live updates when Firebase updates.

import React from 'react';
import { FlatList } from 'react-native';
import { connect } from 'react-redux';
import { subscribe, addTodo, completeTodo } from '../actions/TodoActions.js';
...

class Todos extends React.Component {

  componentDidMount() {
    this.props.dispatch(
      subscribe()
    );
  }
  
  onComplete = (id) => {
    this.props.dispatch(
      completeTodo(id)
    );
  };
  
  onAdd = (text) => {
    this.props.dispatch(
      addTodo(text)
    );
  };
  
  render() {    
    return (
      <FlatList
        data={this.props.todos}
        ...
      />
    );
  }
}

function mapStateToProps(state) {
  return {
    todos: state.todos,
  };
}

export default connect(mapStateToProps)(Todos);