[React Native + Firebase] React Native: Real time database with Firebase -- setup & CRUD

Install:

npm i --save firebase // v3.2.1

Config Firebase:

First we need to require Firebase:

import firebase from 'firebase';

Then in the component constructor, we need to init Firebase:

    constructor(props){
        super(props);
        // Initialize Firebase
        var config = {
            apiKey: "<api_key>",
            authDomain: "<authDomain>",
            databaseURL: "<databaseURL>",
            storageBucket: "<storageBucket>",
        };
        firebase.initializeApp(config);
    }

The config you can easily get from the your Firebase App page.

Create new node: set()

    writeUserData(userId, name, email, imageUrl) {
        firebase.database().ref('users/' + userId).set({
            username: name,
            email: email,
            profile_picture : imageUrl
        });
    }

// calling
    this.writeUserData(, "Zhentian Wan", 'answer881215@gmail.com', null);

Then one node will be created in the "users" node, uid is "1".

Create new Child node: push()

    appendOneMoreUser(name, email, imageUrl){
        let ref = firebase.database().ref().child('users').push({
            username: name,
            email: email
        });
        this.updateMe("Yoona", "yoona.only@gmail.com", ref.key);
    }

// calling
this.appendOneMoreUser("Yuri", 'yuri.only@gmail.com', null);

So under "users" node, we want to append one new node, the uid will be generated randomly.

The "ref" object contains "key" prop which ref to the uid in the database.

Update one node: update()

    updateMe(name, email, key){
        const update = {
            username: name,
            email
        };
        let ref = firebase.database().ref('users/' + key).update(update)
            .then((res)=>{
                console.log("Data has been updated ");
            });
    }

// calling:
const ref = firsebase.database().ref().child('users').push(user);
this.updateMe("Yoona", "yoona.only@gmail.com", ref.key);

update() and set() methods both return Promise. So you can chaining .then() onto it.

Delete node: remove()

    deleteMe(){
        firebase.database().ref('users/1').remove();
    }

Delete the uid = 1 user.