RxJs 地图运算符

Question

我不明白如何解决以下场景中的问题：

getPosts(): Observable<Post[]> {
    return this.http.get<Post[]>(this.postsUrl).pipe(
      tap(() => console.log('fetched posts')),
      catchError(this.handleError<Post[]>('getPosts', []))
    );
  }

.......

export const mapYearWeek = (post: Post): Post => {
  post.time = `
  ${moment(parseInt(post.time)).year()}
  -${moment(parseInt(post.time)).week()}
  `;
  return post;
};

.........

ngOnInit(): void {
    this.postService
      .getPosts()
      .pipe(
        mergeMap(res => res.map(mapYearWeek(post: Post))),  
        tap((res) => console.log(res)),
        groupBy((post: Post) => post.time),
        mergeMap((group) => group.pipe(toArray())),
        tap((res) => console.log(res))
      )
      .subscribe();
  }

我在使用 mapYearweek 函数时遇到错误：

Argument of type 'Post' is not assignable to parameter of type '(value: Post, index: number, array: Post[]) => unknown'. Type 'Post' provides no match for the signature '(value: Post, index: number, array: Post[]): unknown'.ts(2345)

Answer 1

  mergeMap(res => res.map(mapYearWeek(post: Post))),

应该是

  mergeMap(res => res.map(post => mapYearWeek(post))),

RxJs 地图运算符

RxJs map operator

rxjs

angular

rxjs-pipeable-operators

rxjs-observables