How to setup and create services?
Before starting to create a service, you just need to set up a dev environment.
Install Node.js and npm if they are not already on your machine.
Then install the Angular CLI globally.
npm install -g @angular/cli
Angular CLI tool will allow you to easily and quickly generate services, components, pipes, and many more files for your project.
Now, create a new project using the CLI command -
ng new MyProject
And go to your created project directory and launch the server.
ng serve --open
Now come to service - execute below the command for generating service class.
ng g service MyService
It will create the two files in the folder - src/app/
1. my-service.service.spec.ts
2. my-service.service.ts
Now, import my service file into the angular module - app.module.ts file. It looks like this.
import { AppComponent } from './app.component';
import {MyService} from './my-service.service';//Import Service
//AppModule class with @NgModule decorator
@NgModule({
//Static, This is the compiler configuration
//declarations is used for configure the selectors.
declarations: [
AppComponent
],
//Composability and Grouping
//imports used for composing NgModules together.
imports: [
BrowserModule
],
//Runtime or injector configuration
//providers is used for runtime injector configuration.
providers: [MyService],
//bootstrapped entry component
bootstrap: [AppComponent]
})
export class AppModule { }
And let’s see the created service class -my-service.service.ts
import { Injectable } from '@angular/core';
@Injectable()
export class MyService {
constructor() { }
}
Now you need to create service methods to get, post, put, and delete the users.
import { Injectable } from '@angular/core';
@Injectable()
export class MyService {
constructor() { }
//I’m using the static data
//You can also fetch the data using HttpClient service for backend APIs.
users = [
{ "id": 1, "name": "Anil Singh", 'age' :32 },
{ "id": 2, "name": "Aradhya" , 'age' :32},
{ "id": 3, "name": "Reena Singh" , 'age' :32}
]
/* (method) MyService.getUsers(): {
"id": number;
"name": string;
'age': number;
}[] */
getUsers(){
return this.users;
}
}
Now, use this service in the user component for display on UI - my-user.component.ts
import { Component, OnInit } from '@angular/core';
import {MyService} from '../my-service.service';
@Component({
selector: 'app-my-user',
templateUrl: './my-user.component.html',
styleUrls: ['./my-user.component.css']
})
export class MyUserComponent implements OnInit {
userList =[];
constructor(private service :MyService) {
//Get the user list by using the my service.
this.userList = service.getUsers();
}
ngOnInit() { }
}
And my-user.component.html
<h4>User List -</h4>
<table border="1">
<tr>
<th>ID</th><th>Name</th><th>Age</th>
</tr>
<tr *ngFor="let user of userList">
<td>{{user.id}}</td><td>{{user.name}}</td><td>{{user.Age}}</td>
</tr>
</table>
Finally, you got the user list on your components HTML.
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Anil Singh is an author, tech blogger, and software programmer. Book writing, tech blogging is something do extra and Anil love doing it. For more detail, kindly refer to this link..
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