Exploring Angular — Part 6: Services and Dependency Injection
If you missed the previous article on Forms, you can catch up right here: Exploring Angular — Part 5: Forms.
Understanding Angular Services
Imagine Angular services as specialized workers in your application, each responsible for a specific task or handling a unique set of data. These services are the backbone of your application’s functionality, providing a structured and organized way to manage tasks such as data fetching, authentication, and communication with external services.
Angular services are typically classes decorated with the @Injectable() decorator, which tells Angular that the class can be used as a service. Here's an example of a simple Angular service:
import { Injectable } from '@angular/core';
@Injectable({
providedIn: 'root',
})
export class DataService {
private data: string[] = [];
addData(item: string) {
this.data.push(item);
}
getData() {
return this.data;
}
}In this example, we have created a DataService with methods for adding and retrieving data.
The Role of Dependency Injection
Now, imagine your Angular application as a bustling city, and the services as various resources that the city needs to function efficiently. Dependency injection is the mechanism that allows Angular to manage and provide these resources (services) to the parts of your application that need them.
Angular’s dependency injection system ensures that services are created and shared in a way that maximizes efficiency and reduces redundancy. It promotes a modular and maintainable architecture, making your code more organized and easier to test.
How Dependency Injection Works
When your Angular application starts, it creates a dependency injection container, often referred to as the “Injector.” This container holds instances of all the services defined in your application. Whenever a component, directive, or another service needs access to a particular service, Angular’s dependency injection system provides it with an instance of that service.