Firebase App named '[DEFAULT]' already exists (app/duplicate-app) [duplicate]

Answer 1

I had the same issue using firebase, and I discover that I was initializing the firebase twice, example:

function initializeFirebase(){    
 var config = {
    apiKey: "myApiKey",
    authDomain: "myAuthDomain",
    databaseURL: "myDatabaseUrl",
    storageBucket: "myStorageBocket",
    messagingSenderId: "idhere"   
   };   
   //initialize firebase  
   firebase.initializeApp(config);  
}

In my case I was using react, And I was calling initializeFirebase() from two different components, but I've decided to call it from the parent component. And now I'm able to query my database, insert records, remove, etc.

Hope this helps someone

Answer 2

Check if project is in admin.apps. If it is, use if not initialize it. This will prevent the error from occurring.

const projectFbData = admin.apps.find((item) => item.name_ === projectId) || admin.initializeApp(config, projectId)

Answer 3

if (!firebase.apps.length) {
   firebase.initializeApp({});
}else {
   firebase.app(); // if already initialized, use that one
}

Similar answer here

Answer 4

I recently solved this issue in my own code. My issue was caused by accidentally linking my javascript file, which calls initializeApp(), in the head and in the body of my html file. My fix was to delete the duplicate javascript tag in the head of my html file so only one existed in the body.

Scan through your code to make sure you only call initializeApp() once. This includes any js files that might be calling the method or duplicating the js file in your html file.

Answer 5

This error occurs simply because you are trying to initialize firebase multiple times into your project.

Answer 6

// config.js

let config = {
     apiKey: "***********",
    authDomain: "***********",
    databaseURL: "***********",
    projectId: "***********",
    storageBucket: "***********",
    messagingSenderId: "***********",
    appId: "",
    measurementId: "***********"
}

export default config;


// home.js 
import config from '../utils/config'; // import my config file
let db;
setTimeout(() => {
    if (!firebase.apps.length) {
        try {
            firebase.initializeApp(config)
        } catch (err) {
            console.log(err)
        }
    }
    db = firebase.firestore();
}, 1000)