AngularFirestoreCollection get function returns non generic QuerySnapshot

Version info

Angular: 8.2.14

Firebase: 7.14.2

AngularFire: 5.4.2

Ionic: 5.0.7

Capacitor: 2.0.1

How to reproduce these conditions

let users: Array<{ username: string }>

this.fireStore.collection<{ username: string }>('users').get().subscribe(querySnapshot => { users = querySnapshot.docs.map(doc => doc.data()) })

Debug output

Type 'DocumentData[]' is not assignable to type '{ username: string; }[]'. Property 'username' is missing in type 'DocumentData' but required in type '{ username: string; }'.

Expected behavior

The QueryDocumentSnapshot's data() functions return value should be of the type '{ username: string; }'

Actual behavior

Its return value is of the type DocumentData

angular / angularfire