Unable to load data inside ngOnInit

Question

My goal is to load a dropdown when a component renders. I have a service which hits a url and gets json data. Something like this

 @Injectable()
 export class St         


        

Answer 1

The getStudentList method of the service returns an Observable therefore it is an async function. So data => {this.items = data} line performs only after the subscription is completed. But this.items is not undefined since you assign it an empty array with items: any = [], it is only empty.

You can log the values with buttonClicked method because your http request has been completed.

I think you need to get more familiar with Observable from RxJS.

Here is the official docs of HttpClient: https://angular.io/guide/http