Angular7 NgBootstrap Typeahead搜索

Question

我使用的是Angular7，Typeahead 4。我有一个带有NgBootstrap指令的输入域。

当我遵循文档中编写的自定义搜索函数格式时，工作正常。当我尝试修改格式时，我得到一个错误：

我得到了这个错误：

core.js:12584 ERROR TypeError: Cannot set property 'searching' of undefined

我做错了什么？

这是有效的：

 search = (text$: Observable<string>) =>
    text$.pipe(
      debounceTime(300),
      distinctUntilChanged(),
      tap(() => this.searching = true),
      switchMap(term =>

        this.searchService.fetchData(term).pipe(
          tap(() => this.searchFailed = false),
          catchError(() => {
            this.searchFailed = true;
            return of([]);
          }))
      ),

      tap(() => this.searching = false)

    );

这不起作用：

search = function (text$: Observable<string>) {

    return text$.pipe(
      debounceTime(300),
      distinctUntilChanged(),
      tap(() => this.searching = true),
      switchMap(term =>

        this.searchService.fetchData(term).pipe(
          tap(() => this.searchFailed = false),
          catchError(() => {
            this.searchFailed = true;
            return of([]);
          }))
      ),

      tap(() => this.searching = false)

    );

  }

Answer 1

感谢JB Nizet，他给我指明了正确的方向。这是工作代码(参见第一行和最后一行中的花括号)

search = (text$: Observable<string>) => {

    // do some logic before text$.pipe call
    console.log(text$);


    text$.pipe(
      debounceTime(300),
      distinctUntilChanged(),
      tap(() => this.searching = true),
      switchMap(term =>

        this.searchService.fetchData(term).pipe(
          tap(() => this.searchFailed = false),
          catchError(() => {
            this.searchFailed = true;
            return of([]);
          }))
      ),

      tap(() => this.searching = false)

    );

}