Firestore DocumentReference Type Checking mismatch

Issue

When I'm writing the following snippet with the TS compiler option 'strict' enabled, I get a compiler error:

import * as firebase from "firebase/app";
import DocumentReference = firebase.firestore.DocumentReference;
...
this.db.collection('users').doc('admin').ref.get()
  .then(snap => {
    const ref: DocumentReference = snap.ref; // TS2322:Type 'DocumentReference' is not assignable to type 'firebase.firestore.DocumentReference'.
  })

How can I fix this?

(It's a snippet from an Angular project using AngularFire2)

Solution

Your import DocumentReference = firebase.firestore.DocumentReference; is wrong.

Try this way:

import { DocumentReference } from '@firebase/firestore-types';

Answered By - Julius Dzidzevičius