Retry a HTTP get with new configuration parameters each retry

app.ts

//our root app component
import {Component, NgModule} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'
import {HttpModule, Http} from '@angular/http';
import 'rxjs/add/operator/do';
import 'rxjs/add/observable/timer';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/mergeMap';
import 'rxjs/add/operator/retryWhen';
import 'rxjs/add/operator/delay';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/of';

@Component({
  selector: 'my-app',
  template: `
    <div>
      <h2>Hello {{name}}</h2>
    </div>
  `,
})
export class App {
  name:string;
  constructor(private http: Http) {
    Observable.timer(0).mergeMap(x=> {
      return this.http.get('data.json', this.configObject())
      .do(x => throw(x))
      .map(res=>res.json());
    })
    .retryWhen(e => e.delay(2000))
    .subscribe();
    
    /*this.http.get('data.json', this.configObject())
      .do(x => throw(x))
      .map(res=>res.json())
      .retryWhen(e => e.delay(2000))
      .subscribe();*/
  }
  configObject(){
    console.log('*');
  }
}

@NgModule({
  imports: [ BrowserModule, HttpModule ],
  declarations: [ App ],
  bootstrap: [ App ]
})
export class AppModule {}

thank you for sharing this example, I ended up adapting it for my needs. In my case, I needed to call an API with a random string parameter each time until one string passed the test.

  getLetterPair(): Observable<string> {
    return Observable.timer(0).pipe(
      mergeMap(x => {
        this.random = this.padWithRandomLetter()
        return this.wordBankService.checkIfValidFragment(this.random).pipe(
          map(bool => {
            if (!bool) {
              throw (bool)
            }
            return this.random
          })
        )
      }),
      retry(26)
    )
  }