This question already has answers here: Dart, Identifier with exclamation mark in the back (2 answers) In TypeScript, what is the ! (exclamation mark / bang) operator when dereferencing a member? (7 answers) Closed 28 secs ago. _firestore.collection(‘users’).doc(userCredential.user!.uid).set({ In this line, what does the ! next to user do – This is with dart and […]