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What are Angular 17 Services? How to use Angular 17 Service?

Angular Services are reusable pieces of code that can be injected.

Defining a Component, Services are made up of the following:

A TypeScript decorator that declares the class as an Angular service via @Injectable and allows you to define what part of the application can access the service via the providedIn property (which is typically 'root') to allow a service to be accessed anywhere within the application.

A TypeScript class that defines the desired code that will be accessible when the service is injected.

Let's see an example of a Calculator service,

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

@Injectable({

  providedIn: 'root',

})

export class CalculatorService {

  add(a: number, b: number) {

    return a + b;

  }

}

How to use an Angular 17 Service?

When you want to use a service in a component, you need to do the following,

1.     Import the service that you have created.

2.     Declare a class field where the service is injected.

3.     Assign the class field to the result of the call of the Angular built-in function ‘inject’ which creates the service.

See the example of what it looks like,

import { Component } from '@angular/core';

import { CalculatorService } from './calculator.service';

@Component({

  selector: 'app-receipt’,

  template: `<p>The total is {{ totalValue }}</h1>`,

})

export class Receipt {

  private calculatorService = inject(CalculatorService);

  totalValue = this.calculatorService.add(10, 20);

}

In the above example, the service ‘CalculatorService’ is being used by calling the Angular function ‘inject’ and passing in the service to it.


By Anil Singh | Rating of this article (*****)

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