Explain the service in angular.

Question

ICSM Computer · Answer

In Angular, a 
service is a reusable class used to 
share data, logic, or functionality across components. It helps keep components
clean, lightweight, and focused on the UI.
What is a Service in Angular?
An Angular service is:
A TypeScript classUsed to handle business logicUsed for data access (API calls)Used for state sharing between componentsIndependent of UIServices are typically injected into components using Dependency Injection (DI).
Why do we need Services?
Without services:
Components become large and hard to maintainLogic gets duplicatedData sharing between components becomes messy
With services:
Logic is centralizedCode is reusableComponents are loosely coupledEasier to test and maintain
Simple Service Example
Create a service
ng generate service user
This creates:
user.service.ts
Service code
import { Injectable } from '@angular/core';
@Injectable({
  providedIn: 'root'
})
export class UserService {
  getUsers() {
    return ['Alice', 'Bob', 'Charlie'];
  }
}
@Injectable() explained
Marks the class as a serviceAllows Angular to inject dependenciesprovidedIn: 'root' → service is singleton (one instance for the whole app)
Using Service in a Component
import { Component, OnInit } from '@angular/core';
import { UserService } from './user.service';
@Component({
  selector: 'app-user',
  template: `
    andlt;ulandgt;
      andlt;li *ngFor="let user of users"andgt;{{ user }}andlt;/liandgt;
    andlt;/ulandgt;
  `
})
export class UserComponent implements OnInit {
  users: string[] = [];
  constructor(private userService: UserService) {}
  ngOnInit(): void {
    this.users = this.userService.getUsers();
  }
}
Real-world Example: API Call Service
import { HttpClient } from '@angular/common/http';
import { Injectable } from '@angular/core';
@Injectable({
  providedIn: 'root'
})
export class ProductService {
  private apiUrl = 'https://api.example.com/products';
  constructor(private http: HttpClient) {}
  getProducts() {
    return this.http.get(this.apiUrl);
  }
}
Component usage
this.productService.getProducts().subscribe(data =andgt; {
  this.products = data;
});
Service Scope (Where it lives)
1. App-level (Singleton)
@Injectable({ providedIn: 'root' })
One instance for entire app
2. Module-level
providers: [UserService]
One instance per module
3. Component-level
@Component({
  providers: [UserService]
})
New instance per component
Common Uses of Services
HTTP / API communicationAuthentication and AuthorizationLoggingShared state managementUtility functionsWebSocket / SSE handling
Services and Dependency Injection
Angular automatically:
Creates the serviceManages its lifecycleInjects it where needed
constructor(private authService: AuthService) {}
Service vs Component
Component
Service
Handles UI
Handles logic/data
Has template and styles
No template
Tied to view
Reusable across app
Best Practices
Keep components thinMove logic to servicesUse services for API callsAvoid storing UI logic in servicesUse providedIn: 'root' unless scope is needed
Summary
Service = reusable logic/data holderPromotes clean architectureInjected using Dependency InjectionEssential for scalable Angular apps

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Explain the service in angular.

Anubhav Kumar

Can you answer this question?

1 Answers

What is a Service in Angular?

Why do we need Services?

Simple Service Example

Create a service

Service code

`@Injectable()` explained

Using Service in a Component

Real-world Example: API Call Service

Component usage

Service Scope (Where it lives)

1. App-level (Singleton)

2. Module-level

3. Component-level

Common Uses of Services

Services and Dependency Injection

Service vs Component

Best Practices

Summary

Liked By

Component	Service
Handles UI	Handles logic/data
Has template & styles	No template
Tied to view	Reusable across app