---
title: "Explain the service in angular."  
description: "Explain the service in angular."  
author: "Anubhav Sharma"  
published: 2025-12-16  
updated: 2025-12-16  
canonical: https://www.mindstick.com/forum/162010/explain-the-service-in-angular  
category: "technology"  
tags: ["javascript", "angular js", "technology"]  
reading_time: 3 minutes  

---

# Explain the service in angular.

[Explain](https://www.mindstick.com/forum/157854/what-is-system-debugging-explain-some-system-debugging-tools-used-in-modern-computer-systems) the **service** in [angular](https://www.mindstick.com/articles/13081/advantages-disadvantages-of-angularjs-is-that-ideal-for-your-project) with example .

## Replies

### Reply by ICSM Computer

> In Angular, a [**service** is a **reusable class**](https://www.mindstick.com/articles/335832/services-and-dependency-injection-in-angularjs) 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 class**
- Used to handle **business logic**
- Used for **data access (API calls)**
- Used for **state sharing between components**
- **Independent of UI**
- Services are typically injected into components using **Dependency Injection (DI)**.

## Why do we need Services?

## Without services:

- Components become large and hard to maintain
- Logic gets duplicated
- Data sharing between components becomes messy

## With services:

- Logic is **centralized**
- Code is **reusable**
- Components are **loosely coupled**
- Easier to test and maintain

## Simple Service Example

### Create a service

```plaintext
ng generate service user
```

This creates:

```plaintext
user.service.ts
```

### Service code

```javascript
import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class UserService {
  getUsers() {
    return ['Alice', 'Bob', 'Charlie'];
  }
}
```

### `@Injectable()` explained

- Marks the class as a service
- Allows Angular to inject dependencies
- `providedIn: 'root'` → service is **singleton** (one instance for the whole app)

## Using Service in a Component

```javascript
import { Component, OnInit } from '@angular/core';
import { UserService } from './user.service';

@Component({
  selector: 'app-user',
  template: `
    <ul>
      <li *ngFor="let user of users">{{ user }}</li>
    </ul>
  `
})

export class UserComponent implements OnInit {

  users: string[] = [];

  constructor(private userService: UserService) {}

  ngOnInit(): void {
    this.users = this.userService.getUsers();
  }
}
```

## Real-world Example: API Call Service

```javascript
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

```plaintext
this.productService.getProducts().subscribe(data => {
  this.products = data;
});
```

## Service Scope (Where it lives)

### 1. App-level (Singleton)

```javascript
@Injectable({ providedIn: 'root' })
```

One instance for entire app

### 2. Module-level

```javascript
providers: [UserService]
```

One instance per module

### 3. Component-level

```javascript
@Component({
  providers: [UserService]
})
```

New instance per component

## Common Uses of Services

- HTTP / API communication
- Authentication & Authorization
- Logging
- Shared state management
- Utility functions
- WebSocket / SSE handling

## Services and Dependency Injection

Angular automatically:

- Creates the service
- Manages its lifecycle
- Injects it where needed

```javascript
constructor(private authService: AuthService) {}
```

## Service vs Component

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

## Best Practices

- Keep components thin
- Move logic to services
- Use services for API calls
- Avoid storing UI logic in services
- Use `providedIn: 'root'` unless scope is needed

## Summary

- Service = reusable logic/data holder
- Promotes clean architecture
- Injected using Dependency Injection
- Essential for scalable Angular apps


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Original Source: https://www.mindstick.com/forum/162010/explain-the-service-in-angular

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