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How to Create Service in Angular

Last Updated on September 18, 2022 by Climent Rick

Angular is a platform that makes it easy to build applications that the user can interact with. In Angular, there are two ways to create services: using the @Injectable decorator or providing a service provider. The @Injectable decorator is used when you want to create a service that can be injected into other components, while the service provider is used when you want to configure how your service will be created.

  • In your terminal, make sure you are in the directory where your code is located and type “ng generate service name-of-service” to generate a new service file
  • The file will be created in src/app/name-of-service
  • ts with the following boilerplate: import { Injectable } from ‘@angular/core’; @Injectable({ providedIn: ‘root’ }) export class NameOfService { constructor() { } } 3
  • The @Injectable decorator is required when creating services, and marks the class as available to an injector for instantiation
  • The providedIn attribute tells Angular that this service should be created only once, at the root level of our application
  • If we wanted it to be created more than once (e
  • , per component), we could instead use “providers”
  • Inside of our newly generated file, we can define any methods that our service will need
  • For example, let’s say we want a method that returns whether a given number is prime or not: isPrime(num: number) { letprime = true; for(let i = 2; i
  • We can then call this method from anywhere in our application by injecting our NameOfService into the constructor of any component or other service and using the dot notation to access the method, like so:constructor(private nameOfService: NameOfService) {}
  • someFunction() {this
  • nameOfService
  • isPrime(17);}

Ng Generate Service Example

If you’re looking for an example of how to use the Angular CLI’s ng generate service command, look no further! In this post, we’ll go over exactly what this command does and how to use it to create a new service in your Angular application. The ng generate service command is used to generate a new service file in your project.

This file will contain a basic skeleton class that you can fill out with your own code. To use this command, simply navigate to your project’s root directory in the terminal and type: ng generate service my-new-service

This will create a new file called my-new-service.service.ts in the src/app folder of your project. The generated class will look something like this: import { Injectable } from ‘@angular/core’; @Injectable({ providedIn: ‘root’ }) export class MyNewService { constructor() { } }

You can then add whatever methods or properties you need for your service inside of the generated class. Once you’re finished coding your service, don’t forget to register it with the providers array in your app module so that it can be injected into other parts of your application!

Angular Inject Service Without Constructor

There are times when you need to inject a service into an Angular component without using the constructor. This can be done by using the Inject decorator from the @angular/core library. Let’s say we have a component that needs to use the UserService:

import { Component } from ‘@angular/core’; import { UserService } from ‘./user.service’; @Component({ selector: ‘app-root’, templateUrl: ‘./app.component.html’, styleUrls: [‘./app.component.css’] }) export class AppComponent { title = ‘my-app’; constructor(private userService: UserService) { } getCurrentUser() { return this.userService.getCurrentUser(); } } We can use the Inject decorator like this:

Dependency Injection in Angular

Dependency injection (DI) is a software design pattern in which dependencies are injected or passed by reference into a class rather than being hard-coded into the class. This allows for more flexibility and testability in the code. In Angular, dependency injection is used to provide services to classes at runtime.

These services can be injected into any component, directive, pipe, or service. All Angular components need a provider to supply them with services. Angular provides two ways to inject providers: through the providers property of an NgModule or through the use of Injector decorators.

The provider can be registered at any level: root, feature, or component. When multiple providers are registered for the same token, they are merged together into a single provider using a composite strategy that concatenates their lists of dependencies (as seen in the following example). The following example shows how to register a provider with an NgModule:

@NgModule({ providers: [MyService] }) export class MyModule {} In this example, MyService is provided at the root level and will be available throughout the application. If you want to provide MyService only to components declared in MyModule , you can register it with those components instead by listing it under their providers property:

@Component({ selector: ‘my-component’, templateUrl: ‘./my-component.html’, providers:[MyService] }) export class MyComponent {}

Services in Angular

Angular is a platform for building mobile and desktop web applications. AngularJS is its most popular variant, used by Google for such high-profile projects as YouTube, Gmail, and Google Docs. Angular provides two-way data binding, which means that changes to the model are immediately reflected in the view, and vice versa.

This makes it easy to build dynamic user interfaces. Angular also has a powerful directive system that lets you create custom HTML tags that encapsulate complex behavior. directives can be used to create reusable components, or to manipulate the DOM in creative ways.

Services are another key concept in Angular. A service is an injectable class with a well-defined purpose. Services can be used for tasks such as fetching data from a server, logging messages to the console, or interacting with the browser’s localStorage API.

Injectable services make it easy to write code that is modular and testable. They also improve the performance of your application by reducing the amount of code that needs to be executed each time a component is rendered.

Routing in Angular

A routing service is what Angular uses to navigate between pages in your app. It’s responsible for loading and displaying the correct component for a given URL. To use the routing service, you need to add reference to the RouterModule in your AppModule .

The router module provides two directives: RouterLink and RouterOutlet . The router link directive is used to create links to specific routes. The router outlet directive is where the routed component will be displayed.

To configure your routes, you’ll need to provide an array of Route objects to the RouterModule . Each route object has a path and a component property. The path is a string that represents the URL fragment that will be navigated to.

The component property is a reference to the component that should be loaded when that route is accessed. Here’s an example of how you might configure routes for an app with two pages, Home and About : const routes: Routes = [

{ path: ‘home’, component: HomeComponent }, { path: ‘about’, component: AboutComponent } ];

@NgModule({

How to Create Service in Angular
How to Create Service in Angular 2

Credit: code.tutsplus.com

How Services are Created in Angular?

In Angular, services are created by registering them with the Dependency Injection system. This can be done either via the @Injectable decorator or by providing a provider object to the injector. When a service is registered with the DI system, it can be injected into any component or other service that has its provider registered with the same injector.

The most common use case for injecting a service into a component is when the service provides some kind of functionality that the component needs in order to do its job. For example, if we have a component that needs to fetch data from a remote server, we would inject an HTTP client service into it. Another common use case for injecting a service into a component is when the service holds some state that needs to be shared between multiple components.

For example, if we have a user authenticationservice, we would inject it into all components that need access to the authenticated user’s data.

How Do I Create a Service in Angular 8?

Assuming you would like a high-level overview of the process of creating a service in Angular 8: In Angular, a service is an instance of a class that can be made available to any part of your application using Dependency Injection (DI). Services are typically used for performing logic that is not directly related to the user interface.

To create a service, you first need to define it as a class. The class should have @Injectable() decorator. This decorator tells Angular that this class can be injected as a service into other parts of the application.

import { Injectable } from ‘@angular/core’; @Injectable({ providedIn: ‘root’,

}) export class MyService { constructor() { }

public doSomething(): void { // Perform some logic here… }

} After defining the service, you need to register it with Angular’s DI system so that it can be injected into other parts of the application when needed. You can do this using the providers property in one of Angular’s NgModules.

For example, if you were creating a newservice called MyService and wanted to make it available throughout your entire app, you could register it in your root AppModule like this: import { BrowserModule } from ‘@angular/platform-browser’;import { NgModule } from ‘@angular/core’;import { AppComponent } from ‘./app.component’;import { MyService } from ‘./my.service’;@NgModule({declarations: [AppComponent],imports: [BrowserModule],providers: [MyService],bootstrap: [AppComponent]})export class AppModule {} Once your service has been registered with DI, it can be injected into any part of your app by adding it as an argument to the constructor method of the component or directive where you want to use it. For example, if we wanted to inject our MyService into AppComponent , we could do so like this: import { Component } from ‘@angular/core’;import { MyService } from ‘./my.service’;@Component({selector: ‘app-root’,templateUrl: ‘.

How Do I Create a Service in Angular 9?

Assuming that you would like a blog post discussing how to create a service in Angular 9, here is some information that may be helpful. In Angular 9, services are created by using the @Injectable decorator. This decorator tells Angular that this class can be used as a service and that it should be registered in the dependency injector.

Once your service is registered, it can be injected into any component or other service that needs it. Creating a basic service is simple. First, use the angular-cli to generate a new service:

ng generate service my-service This will create a new file called my-service.service.ts in your src/app directory. The contents of this file will look something like this:

import { Injectable } from ‘@angular/core’; @Injectable({ providedIn: ‘root’

}) export class MyServiceService { constructor() { }

public getData() { // Add your code here } // Add more methods here as needed} You can see that there are two things going on here. First, we’re importing the Injectable decorator from @angular/core.

Second, we’re using that decorator on our class to tell Angular that this class can be used as a service and should be registered in the dependency injector (providedIn: ‘root’). The rest of our code goes inside the MyServiceService class definition. We don’t have to do anything special here; just write your code as you normally would for an Angular component or service. In this example, we’ve added a getData() method which doesn’t do anything yet – but you could add whatever functionality you need here. Once your service is defined, you can inject it into any component or other service that needs it using the constructor: constructor(private myService: MyServiceService) {}// Add more code here as needed}Then you can access yourservice’s methods from anywhere in your component by calling this .myServicemethods():this .myComponentMethod(){ // Add more code here as neededconst data = this .myServiceservicegetData();consolelog(” Got data”,data);// Add more code here as needed}}And that’s all there is to creating services in Angular 9!

Why Do We Create Services in Angular?

We create services in Angular for a number of reasons. Services are typically created to perform specific tasks, such as fetching data from an API or storing data in local storage. By creating services, we can keep our code organized and make our applications more scalable.

Additionally, services can be injected into other parts of our application, making them available wherever they’re needed.

Conclusion

In Angular, a service is defined as a class with a @Injectable decorator. The @Injectable decorator is required when using services. When you create a service, you need to register it in the providers array of your NgModule so that Angular can inject it into your components and other services.

Creating services in Angular is easy and there are various ways to do it. In this post, we will explore how to create services using the @Injectable decorator and how to register them in our NgModule . We will also look at how to useservices in our components.

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