Interface 'DatabaseSnapshotExists<T>' incorrectly extends interface 'DataSnapshot'

Version info

Angular: 14.1.1

Firebase: 9.9.2

AngularFire: 7.4.1

Other (e.g. Ionic/Cordova, Node, browser, operating system):

How to reproduce these conditions

Failing test unit, Stackblitz demonstrating the problem https://github.com/wojteko22/angular-fire-bug

Steps to set up and reproduce

1. Clone repo
2. npm install
3. ng serve

Sample data and security rules

Debug output

** Errors in the JavaScript console **

Error: node_modules/@angular/fire/compat/database/interfaces.d.ts:47:18 - error TS2430: Interface 'DatabaseSnapshotExists<T>' incorrectly extends interface 'DataSnapshot'.
  Types of property 'forEach' are incompatible.
    Type '(action: (a: DatabaseSnapshot<T>) => boolean) => boolean' is not assignable to type '(action: (a: DataSnapshot & { key: string; }) => boolean | void) => boolean'.
      Types of parameters 'action' and 'action' are incompatible.
        Types of parameters 'a' and 'a' are incompatible.
          Type 'DatabaseSnapshot<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
            Type 'DatabaseSnapshotExists<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
              Type 'DatabaseSnapshotExists<T>' is not assignable to type 'DataSnapshot'.
                Types of property 'forEach' are incompatible.
                  Type '(action: (a: DatabaseSnapshot<T>) => boolean) => boolean' is not assignable to type '(action: (a: DataSnapshot & { key: string; }) => boolean | void) => boolean'.
                    Types of parameters 'action' and 'action' are incompatible.
                      Types of parameters 'a' and 'a' are incompatible.
                        Type 'DatabaseSnapshot<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
                          Type 'DatabaseSnapshotDoesNotExist<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
                            Type 'DatabaseSnapshotDoesNotExist<T>' is not assignable to type '{ key: string; }'.
                              Types of property 'key' are incompatible.
                                Type 'string | null' is not assignable to type 'string'.
                                  Type 'null' is not assignable to type 'string'.

47 export interface DatabaseSnapshotExists<T> extends firebase.database.DataSnapshot {
                    ~~~~~~~~~~~~~~~~~~~~~~


Error: node_modules/@angular/fire/compat/database/interfaces.d.ts:52:18 - error TS2430: Interface 'DatabaseSnapshotDoesNotExist<T>' incorrectly extends interface 'DataSnapshot'.
  Types of property 'forEach' are incompatible.
    Type '(action: (a: DatabaseSnapshot<T>) => boolean) => boolean' is not assignable to type '(action: (a: DataSnapshot & { key: string; }) => boolean | void) => boolean'.
      Types of parameters 'action' and 'action' are incompatible.
        Types of parameters 'a' and 'a' are incompatible.
          Type 'DatabaseSnapshot<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
            Type 'DatabaseSnapshotDoesNotExist<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
              Type 'DatabaseSnapshotDoesNotExist<T>' is not assignable to type 'DataSnapshot'.
                Types of property 'forEach' are incompatible.
                  Type '(action: (a: DatabaseSnapshot<T>) => boolean) => boolean' is not assignable to type '(action: (a: DataSnapshot & { key: string; }) => boolean | void) => boolean'.
                    Types of parameters 'action' and 'action' are incompatible.
                      Types of parameters 'a' and 'a' are incompatible.
                        Type 'DatabaseSnapshot<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
                          Type 'DatabaseSnapshotExists<T>' is not assignable to type 'DataSnapshot & { key: string; }'.
                            Type 'DatabaseSnapshotExists<T>' is not assignable to type '{ key: string; }'.
                              Types of property 'key' are incompatible.
                                Type 'string | null' is not assignable to type 'string'.
                                  Type 'null' is not assignable to type 'string'.

52 export interface DatabaseSnapshotDoesNotExist<T> extends firebase.database.DataSnapshot {
                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

** Output from firebase.database().enableLogging(true); **

** Screenshots **

Expected behavior

No error in console

Actual behavior

Error in console

Reason

The reason of this error is change of forEach() signature of firebase.database.DataSnapshot in firebase@9.9.2

These are interfaces from @angular/fire:

export interface DatabaseSnapshotExists<T> extends firebase.database.DataSnapshot {
    exists(): true;
    val(): T;
    forEach(action: (a: DatabaseSnapshot<T>) => boolean): boolean;
}
export interface DatabaseSnapshotDoesNotExist<T> extends firebase.database.DataSnapshot {
    exists(): false;
    val(): null;
    forEach(action: (a: DatabaseSnapshot<T>) => boolean): boolean;
}

In firebase@9.9.2 firebase.database.DataSnapshot has such method:

forEach(
  action: (
    a: firebase.database.DataSnapshot & { key: string }
  ) => boolean | void
): boolean;

In firebase@9.9.1 it was:

forEach(
  action: (a: firebase.database.DataSnapshot) => boolean | void
): boolean;

[gorden0929]

Same here Temporarily solution for me: Downgrade typescript to 4.7.4

[edarioq]

Same issue, using angular 15.0.0 - seems to be an issue with compatibility interfaces @angular/fire/compat/firestore/interfaces.d.ts.

This is momentarily fixed by changing the above file, replacing line numbers 15 and 24 to:

data(options?: SnapshotOptions): any;