根据页数动态合并 httpClient Observables

Question

我有 API 部分（按页）提供数据。我在第一次请求时获得页数。

在客户端，我需要在一个 Observable 中连接页面。尝试这样的事情：

all$: Observable<Service[]>;
iterator$ = new BehaviorSubject(1);

constructor(public http: HttpClient) {
  this.all$ = this.iterator$.pipe(
    concatMap(page => http.get<Service[]>('/service', {params: {page: page.toString()}}).pipe(
      tap(() => (ifNotLastPage) ? this.iterator$.next(++page) : null),
    )),
  );
}

并且只获取最后一页

Answer 1

最后我得到了：

all$: Observable<Service[]>;

constructor(public http: HttpClient) {
  this.all$ = this.getData().pipe(
    expand(result => {
      const next = getNextPageNumber(result);

      return (next) ? this.getData(next) : empty();
    }),
    map(result => result.body),
    concatMap(typeCasting(Service)),
    toArray<Service>(),
  );

}

getData(page = 1): Observable<HttpResponse<Config>> {
  return this.http.get<Config>('/service', { observe: 'response', params: { page: page.toString() } });
}

然后 X 到 @martin 和这篇文章 RxJS: Understanding Expand

根据页数动态合并 httpClient Observables

Merging httpClient Observables in one dynamically depending on page count

rxjs

angular

angular-httpclient