angular and firebase: Cannot find namespace 'firebase'

Question

I am getting the below error while working with angular and firebase:

Typescript Error

Cannot find namespace 'firebase'.

C:/Users/DELL/Desktop/connect/withfire/node_modules/angularfire2/auth/auth.d.ts

 app: FirebaseApp; 
 readonly auth: firebase.auth.Auth; 
 readonly authState: Observable<firebase.User | null>; 

Answer 1

You need to downgrade firebase version. Try this: $ npm install -s [email protected]

Answer 2

4.8.1 was a refactor of the typings and you now pull your imports from @firebase:

import { FirebaseApp } from '@firebase/app-types';
import { FirebaseAuth } from '@firebase/auth-types';
import { FirebaseDatabase } from '@firebase/database-types';
import { FirebaseMessaging } from '@firebase/messaging-types';
import { FirebaseStorage } from '@firebase/storage-types';
import { FirebaseFirestore } from '@firebase/firestore-types';

import what ever module you need