13.4.11 - retry

如果 Observable 对象抛出错误，则该辅助方法会重新订阅 Observable 以获取数据流，参数为重新订阅次数

import { interval, of, throwError } from "rxjs"
import { mergeMap, retry } from "rxjs/operators"
interval(1000)
    .pipe(
    mergeMap(val => {
        if (val > 2) {
            return throwError("Error!")
        }
        return of(val)
    }),
    retry(2)
)
.subscribe({
    next: console.log,
    error: console.log
})