Question

我已经用rxjs 5表示法编写了此服务代码：

library(rvest)

url <- "https://www.askebsa.dol.gov/mewaview/View/Index/6219"
nodes <- html_nodes(read_html(url), 'div.question-inline, div.question')
data <- list()

for (i in nodes) {
    n = trimws(html_text(html_node(i, xpath='./text()')))

    if (length(html_nodes(i, 'code')) == 0) {
        text <- html_nodes(i, xpath = '../address/code/text()')
        v <- paste(trimws(text), collapse = '\r\n')
    } else {
        v <- html_text(html_nodes(i, 'code'))
    }
    data[[n]] = v
}

print(data)

我正在尝试将其重构为rxjs 6有效代码，而我现在已经知道了：

      constructor(private _authService: AuthService) {
    this._ws$ = WebSocketSubject.create<any>({
      url: WS_URL,
      protocol: this._authService.token
    });

    this._ws$.retryWhen(errors => {
        // switchMap to retrieve the source error
        return errors.switchMap(sourceErr => {
            console.log('Retry WS.', sourceErr);
            return Observable.timer(1000).map(() => Observable.of(true));
          }
        );
      }
    ).subscribe(
      msg => {
        if ('channel_name' in msg) {
          console.log('Channel name', msg.channel_name);
          this._channelName = msg.channel_name;
          this._authService.channelName = msg.channel_name;
        }
        this.subject$.next(msg);
        console.log(msg);
      },
      err => {
        console.log(err);
        this.subject$.error(err);
      },
      () => this.subject$.complete()
    );
  }

但是我遇到以下错误：

constructor(private _authService: AuthService) {
this._ws$ = WebSocketSubject.create({
  url: WS_URL,
  protocol: this._authService.token
});

retryWhen(() => {
    // switchMap to retrieve the source error
    return switchMap(() => {
        return timer(1000).pipe(map(() => of(true)));
      }
    );
  }
).subscribe(
  msg => {
    if ('channel_name' in msg) {
      this._channelName = msg.channel_name;
      this._authService.channelName = msg.channel_name;
    }
    this.subject$.next(msg);
  },
  err => {
    this.subject$.error(err);
  },
  () => this.subject$.complete()
);

我不知道在这里使用retryWhen函数的最佳方法是什么，以及如何在其中使用WebSocketSubject。

Answer 1

Rxjs 6中上述代码的实现看起来像下面的

 this._ws$.pipe(
  retryWhen(errors =>
    errors.pipe(
      tap(val => console.log('Retry WS.', val)),
      delay(1000)
    )
  )).subscribe( msg => {
    if ('channel_name' in msg) {
      this._channelName = msg.channel_name;
      this._authService.channelName = msg.channel_name;
    }
    this.subject$.next(msg);
  },err => {
    this.subject$.error(err);
  },() => this.subject$.complete()
  );

有关使用Rxjs 6时重试的更多信息，请参考此处
https://www.learnrxjs.io/operators/error_handling/retrywhen.html

将rxjs 5重构为rxjs 6代码-retryWhen

1 个答案: