angular 4 cannot read property 'id' of undefined

user_7023946 0
Viewed 33968

i'm trying to use angular 4 to call to a dummy web api, here is my component 

export class AppComponent {
    title = 'app';
    url = 'https://api.ipify.org/?format=json';
    results: any;

    constructor(private http: Http) {
        this.getData().subscribe(data => {
            this.results = data.json();
        })
    }

    getData() {
        return this.http.get(this.url);
    }

}


but when i try to display it i get the result but also a screen of error 

ERROR TypeError: Cannot read property 'ip' of undefined

what i want to understand is why it is shown because after a split second the data is well displayed .

angular
7 Answers

You get this error also if you add your component to the import array instead of the declaration array.

@NgModule({
  imports: [
    ...,
    someComponent
  ],

  declarations: [...],
})
export class MainModule { }

Should be

@NgModule({
  imports: [
    ...,
  ],

  declarations: [...,someComponent],
})
export class MainModule { }
user_50317870

if you have more than one property you can use a class and inject them there , then it would be no problem . otherwise if you have just one single variable and u want it to be displayed pls use the safe navigation operator user?.name

user_73760330
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