WEB-896: Add debounced dynamic search to client list

Author: Agaba-Ed

src/app/clients/clients.component.html

@@ -14,8 +14,18 @@
           matInput
           placeholder="{{ 'labels.text.SearchByClient' | translate }}"
           class="search-box"
+          #searchInput
+          (input)="onSearchInput($event.target.value)"
           (keydown.enter)="search($event.target.value)"
         />
+        <button
+          mat-icon-button
+          matSuffix
+          (click)="search(searchInput.value)"
+          [attr.aria-label]="'labels.buttons.Search' | translate"
+        >
+          <mat-icon>search</mat-icon>
+        </button>
       </mat-form-field>
     </div>
     @if (existsClientsToFilter) {

src/app/clients/clients.component.spec.ts

@@ -0,0 +1,122 @@
+/**
+ * Copyright since 2025 Mifos Initiative
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+import { ComponentFixture, TestBed } from '@angular/core/testing';
+import { of } from 'rxjs';
+import { ClientsComponent } from './clients.component';
+import { ClientsService } from './clients.service';
+import { AuthenticationService } from 'app/core/authentication/authentication.service';
+import { TranslateModule } from '@ngx-translate/core';
+import { provideAnimationsAsync } from '@angular/platform-browser/animations/async';
+import { provideRouter } from '@angular/router';
+import { FaIconLibrary } from '@fortawesome/angular-fontawesome';
+import * as solidIcons from '@fortawesome/free-solid-svg-icons';
+import { describe, it, expect, jest, beforeEach, afterEach } from '@jest/globals';
+
+describe('ClientsComponent — debounce search', () => {
+  let component: ClientsComponent;
+  let fixture: ComponentFixture<ClientsComponent>;
+  let clientsService: jest.Mocked<ClientsService>;
+
+  const DEBOUNCE_MS = 500;
+  const emptyPage = { content: [] as any[], totalElements: 0, numberOfElements: 0 };
+
+  beforeEach(async () => {
+    jest.useFakeTimers();
+
+    clientsService = {
+      searchByText: jest.fn(() => of(emptyPage))
+    } as any;
+
+    const authService = { getCredentials: jest.fn(() => ({ permissions: ['ALL_FUNCTIONS'] })) } as any;
+
+    await TestBed.configureTestingModule({
+      imports: [
+        ClientsComponent,
+        TranslateModule.forRoot()
+      ],
+      providers: [
+        { provide: ClientsService, useValue: clientsService },
+        { provide: AuthenticationService, useValue: authService },
+        provideAnimationsAsync(),
+        provideRouter([])
+      ]
+    }).compileComponents();
+
+    const faIconLibrary = TestBed.inject(FaIconLibrary);
+    const iconList = Object.keys(solidIcons)
+      .filter((key) => key !== 'fas' && key !== 'prefix' && key.startsWith('fa'))
+      .map((icon) => (solidIcons as any)[icon]);
+    faIconLibrary.addIcons(...iconList);
+
+    fixture = TestBed.createComponent(ClientsComponent);
+    component = fixture.componentInstance;
+    fixture.detectChanges();
+
+    // Reset call count from ngOnInit (preloadClients may trigger a call)
+    clientsService.searchByText.mockClear();
+  });
+
+  afterEach(() => {
+    jest.useRealTimers();
+  });
+
+  it('should not search before 500 ms have elapsed', () => {
+    component.onSearchInput('alice');
+    jest.advanceTimersByTime(DEBOUNCE_MS - 1);
+    expect(clientsService.searchByText).not.toHaveBeenCalled();
+  });
+
+  it('should search after 500 ms pause', () => {
+    component.onSearchInput('alice');
+    jest.advanceTimersByTime(DEBOUNCE_MS);
+    expect(clientsService.searchByText).toHaveBeenCalledTimes(1);
+    expect(clientsService.searchByText).toHaveBeenCalledWith('alice', 0, expect.any(Number), '', '');
+  });
+
+  it('should reset the timer on rapid typing and fire only once', () => {
+    component.onSearchInput('a');
+    jest.advanceTimersByTime(200);
+    component.onSearchInput('al');
+    jest.advanceTimersByTime(200);
+    component.onSearchInput('ali');
+    jest.advanceTimersByTime(DEBOUNCE_MS);
+    expect(clientsService.searchByText).toHaveBeenCalledTimes(1);
+    expect(clientsService.searchByText).toHaveBeenCalledWith('ali', 0, expect.any(Number), '', '');
+  });
+
+  it('should ignore duplicate consecutive values', () => {
+    component.onSearchInput('alice');
+    jest.advanceTimersByTime(DEBOUNCE_MS);
+    component.onSearchInput('alice');
+    jest.advanceTimersByTime(DEBOUNCE_MS);
+    expect(clientsService.searchByText).toHaveBeenCalledTimes(1);
+  });
+
+  it('should search immediately when Enter is pressed', () => {
+    component.search('bob');
+    expect(clientsService.searchByText).toHaveBeenCalledTimes(1);
+    expect(clientsService.searchByText).toHaveBeenCalledWith('bob', 0, expect.any(Number), '', '');
+  });
+
+  it('should not fire a second request when Enter is pressed while debounce is pending', () => {
+    component.onSearchInput('dave');
+    jest.advanceTimersByTime(200);
+    component.search('dave');
+    expect(clientsService.searchByText).toHaveBeenCalledTimes(1);
+    jest.advanceTimersByTime(DEBOUNCE_MS);
+    expect(clientsService.searchByText).toHaveBeenCalledTimes(1);
+  });
+
+  it('should not fire debounced search after component is destroyed', () => {
+    component.onSearchInput('carol');
+    component.ngOnDestroy();
+    jest.advanceTimersByTime(DEBOUNCE_MS);
+    expect(clientsService.searchByText).not.toHaveBeenCalled();
+  });
+});

src/app/clients/clients.component.ts

@@ -7,7 +7,7 @@
  */
 
 /** Angular Imports. */
-import { Component, OnInit, ViewChild, inject } from '@angular/core';
+import { Component, OnInit, OnDestroy, ViewChild, inject } from '@angular/core';
 import { MatCheckbox } from '@angular/material/checkbox';
 import { MatPaginator, PageEvent } from '@angular/material/paginator';
 import { MatSort, Sort, MatSortHeader } from '@angular/material/sort';
@@ -24,6 +24,12 @@ import {
   MatRowDef,
   MatRow
 } from '@angular/material/table';
+import { MatIconButton } from '@angular/material/button';
+import { MatIcon } from '@angular/material/icon';
+
+/** rxjs Imports */
+import { Subject } from 'rxjs';
+import { debounceTime, distinctUntilChanged, takeUntil } from 'rxjs/operators';
 
 /** Custom Services */
 import { environment } from '../../environments/environment';
@@ -61,12 +67,17 @@ import { STANDALONE_SHARED_IMPORTS } from 'app/standalone-shared.module';
     MatRowDef,
     MatRow,
     MatPaginator,
-    StatusLookupPipe
+    StatusLookupPipe,
+    MatIconButton,
+    MatIcon
   ]
 })
-export class ClientsComponent implements OnInit {
+export class ClientsComponent implements OnInit, OnDestroy {
   private clientService = inject(ClientsService);
 
+  private destroy$ = new Subject<void>();
+  private searchInput$ = new Subject<string>();
+
   /** Returns true if client data masking is enabled */
   get hideClientData(): boolean {
     return environment.complianceHideClientData;
@@ -109,11 +120,26 @@ export class ClientsComponent implements OnInit {
   @ViewChild(MatSort) sort: MatSort;
 
   ngOnInit() {
+    this.searchInput$.pipe(debounceTime(500), distinctUntilChanged(), takeUntil(this.destroy$)).subscribe((value) => {
+      if (value !== this.filterText) {
+        this.search(value);
+      }
+    });
+
     if (environment.preloadClients) {
       this.getClients();
     }
   }
 
+  ngOnDestroy() {
+    this.destroy$.next();
+    this.destroy$.complete();
+  }
+
+  onSearchInput(value: string) {
+    this.searchInput$.next(value);
+  }
+
   /**
    * Searches server for query and resource.
    */