Fixes NgZone Issues in angularfire auth as described in https://github.com/angular/angularfire/issues/2355

angular-fire-auth-guard-fix.guard.ts

import { Injectable, Inject, Optional, NgZone } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, Router } from '@angular/router';
import { Observable, of, pipe, UnaryFunction } from 'rxjs';
import { map, switchMap, take, observeOn, shareReplay } from 'rxjs/operators'
import { User } from 'firebase/app';
import { ɵAngularFireSchedulers, FirebaseOptions, FirebaseAppConfig, FIREBASE_OPTIONS, FIREBASE_APP_NAME, ɵfirebaseAppFactory, ɵZoneScheduler } from '@angular/fire';

export type AuthPipeGenerator = (next: ActivatedRouteSnapshot, state: RouterStateSnapshot) => AuthPipe;
export type AuthPipe = UnaryFunction<Observable<User | null>, Observable<boolean | any[]>>;

@Injectable({
	providedIn: 'any'
})
export class AngularFireAuthGuardFix implements CanActivate {

	authState: Observable<User | null>;
	zone: NgZone;

	constructor(
		@Inject(FIREBASE_OPTIONS) options: FirebaseOptions,
		@Optional() @Inject(FIREBASE_APP_NAME) nameOrConfig: string | FirebaseAppConfig | null | undefined,
		zone: NgZone,
		private router: Router
	) {
		const auth = of(undefined).pipe(
			// observeOn(new ɵAngularFireSchedulers(zone).outsideAngular),
			// switchMap(() => zone.runOutsideAngular(() => import('firebase/auth'))),
			// observeOn(new ɵAngularFireSchedulers(zone).insideAngular),
			switchMap(() => zone.run(() => import('firebase/auth'))),
			map(() => ɵfirebaseAppFactory(options, zone, nameOrConfig)),
			map(app => app.auth()),
			shareReplay({ bufferSize: 1, refCount: false }),
		);

		this.authState = auth.pipe(
			switchMap(auth => new Observable<User | null>(auth.onAuthStateChanged.bind(auth)))
		);
	}

	canActivate = (next: ActivatedRouteSnapshot, state: RouterStateSnapshot) => {
		const authPipeFactory = next.data.authGuardPipe as AuthPipeGenerator || (() => loggedIn);
		return this.authState.pipe(
			take(1),
			authPipeFactory(next, state),
			map(can => typeof can == "boolean" ? can : this.router.createUrlTree(<any[]>can))
		);
	}

}

export const canActivate = (pipe: AuthPipeGenerator) => ({
	canActivate: [AngularFireAuthGuardFix], data: { authGuardPipe: pipe }
});

export const loggedIn: AuthPipe = map(user => !!user);
export const isNotAnonymous: AuthPipe = map(user => !!user && !user.isAnonymous);
export const idTokenResult = switchMap((user: User | null) => user ? user.getIdTokenResult() : of(null));
export const emailVerified: AuthPipe = map(user => !!user && user.emailVerified);
export const customClaims = pipe(idTokenResult, map(idTokenResult => idTokenResult ? idTokenResult.claims : []));
export const hasCustomClaim = (claim: string) => pipe(customClaims, map(claims => claims.hasOwnProperty(claim)));
export const redirectUnauthorizedTo = (redirect: any[]) => pipe(loggedIn, map(loggedIn => loggedIn || redirect));
export const redirectLoggedInTo = (redirect: any[]) => pipe(loggedIn, map(loggedIn => loggedIn && redirect || true));

Summary

Full disclosure this is copied from https://github.com/angular/angularfire/blob/master/src/auth-guard/auth-guard.ts and fixes angular/angularfire#2355 as a quick workaround.

The important changes can be found in https://gist.github.com/vsaw/d9c340d2151965dbdd6747943664a4dd#file-angular-fire-auth-guard-fix-guard-ts-L26-L29

License

The MIT License

Copyright (c) 2020, Valentin Sawadski

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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The above copyright notice and this permission notice shall be included in
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