How To Get User Specific Data By UID in Firebase [RTDB]

#javascript #firebase #programming

One of the questions I have been asked a lot about Firebase is:

How to get currently logged-in user data from Firebase Real-Time Database?

Let’s see how to do that in action.

I am assuming that you already know how to create a project in Firebase, add an appropriate Firebase Product SDKs, and initialization code to your project.

Recommended: Create A Firebase Project and Get Initialization Code

Implement Firebase Authentication
Add Logged In User Data
Get Logged In User Data
Protect User Data Using Security Rules

Implement Firebase Authentication

Add Firebase Auth SDK CDN to your HTML file.

<script src="https://www.gstatic.com/firebasejs/6.6.1/firebase-auth.js"></script>

Make sure to enable the Email/Password option under the Sign-in Method tab on the Firebase Authentication page.

Being lazy, I added an email and the password values hardcoded rather than getting them from HTML input elements.

var email = "raja@gmail.com"
var password = "pword1"

async function createNewAccount() {
    try {
        const user = await firebase.auth().createUserWithEmailAndPassword(email, password);
        console.log(user.uid)
    } catch (error) {
        console.log(error.message)
    }
}

When you invoke createNewAccount() on page load, a brand new Firebase account will be created on the Firebase Authentication page.

Recommended: FirebaseUI + Vue.js: Build A Complete Social Login Page

Get User Data Using Auth() Object

As soon as a new Firebase account is created, you’re in a logged-in state and user’s auth object is available inside onAuthStateChange() method.

firebase.auth().onAuthStateChanged(user => {<br>  if(user) {
    console.log(user.uid)<br>    console.log(user.email)<br>   }
})

User’s auth object will have some data about the logged-in user. If you want to add some additional information such as phone and address, you will need to store them into the real-time database.

Recommended
Learn Firebase Storage Quickly [Guide]

Add User Data To The Database

Once userAuth object becomes available, compose a user object with properties like name, phone, address, etc including uid and email from userAuth object.

Then, pass it to the writeUserData() function as an argument.

async function createNewAccount() {
    try {
        const userAuth = await firebase.auth().createUserWithEmailAndPassword(email, password);
        var user = {
            name: "Raja",
            phone: "779797329",
            address: "474 Mercer Drive",
            uid: userAuth.uid,
            email: userAuth.email
        }
        writeUserData(user)

    } catch (error) {
        console.log(error.message)
    }
}