What are the steps for fetching the data with Http Client & Observable Angular?053

  What are the steps for fetching the data with Http Client & Observable Angular?

Here are the steps for fetching data with HttpClient and Observables in Angular:

1. Import necessary modules:

• In your component's module file (e.g., app.module.ts), import HttpClientModule from @angular/common/http.

TypeScript

import { BrowserModule } from '@angular/platform-browser';
import { HttpClientModule } from '@angular/common/http';
// ... other imports

@NgModule({
  imports: [
    BrowserModule,
    HttpClientModule,
    // ... other modules
  ],
  // ...
})
export class AppModule { }

2. Inject HttpClient in your component:

• In your component class, inject the HttpClient service through the constructor.

TypeScript

import { Component, OnInit } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Component({
  selector: 'app-my-component',
  templateUrl: './my-component.component.html',
  styleUrls: ['./my-component.component.css']
})
export class MyComponent implements OnInit {
  data: any[];

  constructor(private http: HttpClient) {}

  ngOnInit(): void {
    // Make the request here
  }
}

3. Make the HTTP request:

• Use the appropriate HTTP method (get, post, put, delete, etc.) of HttpClient to make the request to your API endpoint. The method returns an Observable.

TypeScript

ngOnInit(): void {
  this.http.get<any[]>('https://api.example.com/data')
    .subscribe(data => {
      this.data = data;
    }, error => {
      console.error('Error fetching data:', error);
    });
}

4. Subscribe to the Observable:

• Call the subscribe method on the Observable returned by the HTTP method. This initiates the request and provides handlers for both successful and error responses.

• In the success callback (first argument to subscribe), handle the received data (e.g., store it in a component property).

• In the error callback (second argument to subscribe), handle any errors that occur during the request or response.

5. Display or use the data:

• In your component template, use the data stored in the component property to display or manipulate it as needed.

Additional considerations:

• You can customize the http.get call with options like headers, body, etc.

• Use RxJS operators like map, catchError, etc. to transform or handle the data stream within the subscription.

• Remember to unsubscribe from the Observable when the component is destroyed to avoid memory leaks.

For further learning, explore the official Angular documentation and examples:

• https://angular.io/tutorial/tour-of-heroes/toh-pt6

• https://stackoverflow.com/questions/50606752/angular-using-the-equivalent-of-requestoptions-of-http-with-httpclient

• https://angular.io/guide/rx-library

I hope this helps!

Sources

1. https://github.com/MaxRukavitcyn/ClientTestTaskForIBS

2. https://mygeekssupport.com/web-development-framework-angular/