RxJS -重试或重置

import { of } from 'rxjs';
import { ajax } from 'rxjs/ajax';
import { retry } from 'rxjs/operators';

const source$ = ajax.getJSON('https://api.example.com/data').pipe(
  retry(3)
);

source$.subscribe(
  data => console.log(data),
  error => console.error(error)
);

import { of } from 'rxjs';
import { repeat } from 'rxjs/operators';

const source$ = of('Hello World').pipe(
  repeat(3)
);

source$.subscribe(
  data => console.log(data)
);