Angular Reactive Forms: Difficulty Validating Nested Form Groups with Async Validators
Quick question that's been bugging me - After trying multiple solutions online, I still can't figure this out... I'm currently working with Angular Reactive Forms and working with an scenario with validating nested FormGroups that include async validators. I've set up a form with a main FormGroup which contains a nested FormGroup for 'address'. The 'address' FormGroup has an async validator that checks if the street name already exists in the database. However, the validation seems to not trigger correctly when the form loads, and I receive an 'Unexpected behavior' message in the console instead of my expected validation outcomes. Here's a snippet of my form setup: ```typescript import { Component, OnInit } from '@angular/core'; import { FormBuilder, FormGroup, Validators } from '@angular/forms'; import { AddressService } from './address.service'; @Component({ selector: 'app-user-form', templateUrl: './user-form.component.html' }) export class UserFormComponent implements OnInit { userForm: FormGroup; constructor(private fb: FormBuilder, private addressService: AddressService) {} ngOnInit() { this.userForm = this.fb.group({ name: ['', Validators.required], address: this.fb.group({ street: ['', [Validators.required], [this.streetExists.bind(this)]], city: ['', Validators.required] }) }); } streetExists(control) { return this.addressService.checkStreetExists(control.value).pipe( map(exists => (exists ? { streetExists: true } : null)), catchError(() => of(null)) ); } } ``` In my `AddressService`, I'm making an HTTP call to check if the street exists: ```typescript import { Injectable } from '@angular/core'; import { HttpClient } from '@angular/common/http'; import { Observable } from 'rxjs'; @Injectable({ providedIn: 'root' }) export class AddressService { constructor(private http: HttpClient) {} checkStreetExists(street: string): Observable<boolean> { return this.http.get<boolean>(`/api/address/check?street=${street}`); } } ``` When I load the form, the console shows an 'Unexpected behavior' without any stack trace. I've confirmed that the API endpoint is correct and returns a proper boolean value. I also tried moving the async validator to the parent FormGroup, but the behavior remains the same. Any insights on why my async validator isn't triggering properly or how to better debug this scenario would be really appreciated. Am I approaching this the right way?