Add the search feature to your app

This tutorial lesson demonstrates how to add a search functionality to your Angular app.

The app will enable users to search through the data provided by your app and display only the results that match the entered term.

What you'll learn

• Your app will use data from a form to search for matching housing locations
• Your app will display only the matching housing locations

1. Update the home component properties

   In this step, you'll update the HomeComponent class to store data in a new array property that you will use for filtering.

   1. In src/app/home/home.component.ts, add new property to the class called filteredLocationList.

      Add the filtered results property

            
      import {Component, inject} from '@angular/core';import {CommonModule} from '@angular/common';import {HousingLocationComponent} from '../housing-location/housing-location.component';import {HousingLocation} from '../housinglocation';import {HousingService} from '../housing.service';@Component({  selector: 'app-home',  standalone: true,  imports: [CommonModule, HousingLocationComponent],  template: `    <section>      <form>        <input type="text" placeholder="Filter by city" #filter />        <button class="primary" type="button" (click)="filterResults(filter.value)">Search</button>      </form>    </section>    <section class="results">      <app-housing-location        *ngFor="let housingLocation of filteredLocationList"        [housingLocation]="housingLocation"      ></app-housing-location>    </section>  `,  styleUrls: ['./home.component.css'],})export class HomeComponent {  housingLocationList: HousingLocation[] = [];  housingService: HousingService = inject(HousingService);  filteredLocationList: HousingLocation[] = [];  constructor() {    this.housingLocationList = this.housingService.getAllHousingLocations();    this.filteredLocationList = this.housingLocationList;  }  filterResults(text: string) {    if (!text) {      this.filteredLocationList = this.housingLocationList;      return;    }    this.filteredLocationList = this.housingLocationList.filter((housingLocation) =>      housingLocation?.city.toLowerCase().includes(text.toLowerCase()),    );  }}
          

      The filteredLocationList hold the values that match the search criteria entered by the user.

   2. The filteredLocationList should contain the total set of housing locations values by default when the page loads. Update the constructor for the HomeComponent to set the value.

   Set the value of filteredLocationList

         
   import {Component, inject} from '@angular/core';import {CommonModule} from '@angular/common';import {HousingLocationComponent} from '../housing-location/housing-location.component';import {HousingLocation} from '../housinglocation';import {HousingService} from '../housing.service';@Component({  selector: 'app-home',  standalone: true,  imports: [CommonModule, HousingLocationComponent],  template: `    <section>      <form>        <input type="text" placeholder="Filter by city" #filter />        <button class="primary" type="button" (click)="filterResults(filter.value)">Search</button>      </form>    </section>    <section class="results">      <app-housing-location        *ngFor="let housingLocation of filteredLocationList"        [housingLocation]="housingLocation"      ></app-housing-location>    </section>  `,  styleUrls: ['./home.component.css'],})export class HomeComponent {  housingLocationList: HousingLocation[] = [];  housingService: HousingService = inject(HousingService);  filteredLocationList: HousingLocation[] = [];  constructor() {    this.housingLocationList = this.housingService.getAllHousingLocations();    this.filteredLocationList = this.housingLocationList;  }  filterResults(text: string) {    if (!text) {      this.filteredLocationList = this.housingLocationList;      return;    }    this.filteredLocationList = this.housingLocationList.filter((housingLocation) =>      housingLocation?.city.toLowerCase().includes(text.toLowerCase()),    );  }}
       

2. Update the home component template

   The HomeComponent already contains an input field that you will use to capture input from the user. That string text will be used to filter the results.

   1. Update the HomeComponent template to include a template variable in the input element called #filter.

      Add a template variable to HomeComponent's template

            
      <input type="text" placeholder="Filter by city" #filter>
          

      This example uses a template reference variable to get access to the input element as its value.

   2. Next, update the component template to attach an event handler to the "Search" button.

      Bind the click event

            
      <button class="primary" type="button" (click)="filterResults(filter.value)">Search</button>
          

      By binding to the click event on the button element, you are able to call the filterResults function. The argument to the function is the value property of the filter template variable. Specifically, the .value property from the input HTML element.

   3. The last template update is to the ngFor directive. Update the ngFor value to iterate over values from the filteredLocationList array.

   Update the ngFor directive value

         
   <app-housing-location *ngFor="let housingLocation of filteredLocationList" [housingLocation]="housingLocation"></app-housing-location>
       

3. Implement the event handler function

   The template has been updated to bind the filterResults function to the click event. Next, your task is to implement the filterResults function in the HomeComponent class.

   1. Update the HomeComponent class to include the implementation of the filterResults function.

      Add the filterResults function implementation

            
      import {Component, inject} from '@angular/core';import {CommonModule} from '@angular/common';import {HousingLocationComponent} from '../housing-location/housing-location.component';import {HousingLocation} from '../housinglocation';import {HousingService} from '../housing.service';@Component({  selector: 'app-home',  standalone: true,  imports: [CommonModule, HousingLocationComponent],  template: `    <section>      <form>        <input type="text" placeholder="Filter by city" #filter />        <button class="primary" type="button" (click)="filterResults(filter.value)">Search</button>      </form>    </section>    <section class="results">      <app-housing-location        *ngFor="let housingLocation of filteredLocationList"        [housingLocation]="housingLocation"      ></app-housing-location>    </section>  `,  styleUrls: ['./home.component.css'],})export class HomeComponent {  housingLocationList: HousingLocation[] = [];  housingService: HousingService = inject(HousingService);  filteredLocationList: HousingLocation[] = [];  constructor() {    this.housingLocationList = this.housingService.getAllHousingLocations();    this.filteredLocationList = this.housingLocationList;  }  filterResults(text: string) {    if (!text) {      this.filteredLocationList = this.housingLocationList;      return;    }    this.filteredLocationList = this.housingLocationList.filter((housingLocation) =>      housingLocation?.city.toLowerCase().includes(text.toLowerCase()),    );  }}
          

      This function uses the String filter function to compare the value of the text parameter against the housingLocation.city property. You can update this function to match against any property or multiple properties for a fun exercise.

   2. Save your code.

   3. Refresh the browser and confirm that you can search the housing location data by city when you click the "Search" button after entering text.

   

For more information about the topics covered in this lesson, visit: