"Exploring the incredible powers of Ionic2, Angular2, HTTP requests, and

Despite all the research I've done on observables, I still struggle to grasp how they function.

The HTTP request code snippet is as follows:

import { Component, OnInit, Injectable } from '@angular/core';
import { Http, Response, Headers, RequestOptions } from '@angular/http';
import { NavController } from 'ionic-angular';
import { Observable } from 'rxjs/Rx';    
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';

@Injectable()
@Component({
  selector: 'page-home',
  templateUrl: 'home.html'
})
export class HomePage {

    webs: any;

    getWebs(): any{
        return this.http.get( 'here the url' )
        .map((res: Response) => res.json());
    }

    constructor(public navCtrl: NavController, private http: Http) {}

    ngOnInit(){
        this.getWebs().subscribe(response => {
            this.webs = response;
            console.log(this.webs);
        });
    }
}

While the console displays "this.webs" correctly, indicating that the GET request is successful and the desired object is retrieved (a typical JSON object), an issue arises when trying to display a specific property of the object in the view. For example:

{{ webs.name }}

This consistently results in the following error being thrown:

Error in ./HomePage class HomePage - caused by: Cannot read property 'name' of undefined

In Angular 1, this task was much simpler. Despite consulting various tutorials, I haven't found a solution to this problem yet. Your assistance would be greatly appreciated.

Answer №1

The display is presented prior to receiving the http response.

{{webs?.name}}

It should function properly. Alternatively, execute this.webs=getWebs() and {{webs.name | async}}

Answer №2

It should definitely be something

this.acquireWebs().then((webs) => {
   webs.subscribe(response => {
      this.webs = response;
       resolve(webs);
       console.log(this.webs);
   });
})

After retrieving the Webs content, make sure to execute this part of the code. This snippet has not been tested yet, but the concept is clear. Don't call functions before receiving the necessary data.

 ngOnInit(){
    return new Promise(resolve => {
       this.http.get('webs.json')
           .map(res => res.json())
             .subscribe(webs => {
                  this.webs = webs;
                  resolve(this.webs);
             });
           });
  } 

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