feat(pokemon): debounce async validator and reset validating state in finalize

src/app/core/validators/pokemon.validator.ts

@@ -1,5 +1,5 @@
 import type { Observable } from 'rxjs';
-import { catchError, map, of } from 'rxjs';
+import { catchError, finalize, map, of, switchMap, tap, timer } from 'rxjs';
 import { inject, Injectable, signal } from '@angular/core';
 import type { AbstractControl, AsyncValidator, ValidationErrors } from '@angular/forms';
 import { PokemonService } from '~features/pokemon/services/pokemon.service';
@@ -8,30 +8,40 @@ import { PokemonService } from '~features/pokemon/services/pokemon.service';
 export class PokemonValidator implements AsyncValidator {
   private readonly pokemonService = inject(PokemonService);
   private readonly pokemonName = signal('');
+  private readonly debounceMs = 500;
 
   readonly pokemonId = signal(-1);
   readonly isPokemonValidating = signal(false);
 
-  validate(control: AbstractControl): Observable<ValidationErrors | null> {
+  validate(control: AbstractControl<string | null>): Observable<ValidationErrors | null> {
     const pokemonName = (control.value ?? '').toLowerCase().trim();
 
     if (!pokemonName) {
       this.isPokemonValidating.set(false);
+      this.pokemonId.set(-1);
       return of(null);
     }
 
-    this.pokemonName.set(pokemonName.toLowerCase());
+    this.pokemonName.set(pokemonName);
     this.isPokemonValidating.set(true);
-    return this.pokemonService.getPokemon(pokemonName.toLowerCase()).pipe(
-      map((pokemon) => {
+    return this.validatePokemonName(pokemonName).pipe(
+      finalize(() => {
         this.isPokemonValidating.set(false);
-        this.pokemonId.set(pokemon.id);
-        return null;
-      }),
-      catchError(() => {
-        this.isPokemonValidating.set(false);
-        return of({ pokemonName: true });
       }),
     );
   }
+
+  private validatePokemonName(pokemonName: string): Observable<ValidationErrors | null> {
+    return timer(this.debounceMs).pipe(
+      switchMap(() =>
+        this.pokemonService.getPokemon(pokemonName).pipe(
+          tap((pokemon) => {
+            this.pokemonId.set(pokemon.id);
+          }),
+          map(() => null),
+          catchError(() => of({ pokemonName: true })),
+        ),
+      ),
+    );
+  }
 }