javascript - 无法将订阅的可观察对象作为字符串放入集合中

Question

我是 typescript 和 javascript 的新手，我真的很难搞清楚集合和文件 io 是如何工作的。我正在尝试从 json 文件中获取数据，尽管当我将其放入集合中时该集合没有数据，但我成功了。

代码如下:

在我的服务类中:

  private configuration = "../../assets/Configurations/testConfiguration.json";

  constructor(private http: HttpClient) {}

  getBlogs(blog: string): Observable<IBlogPost[]> {
    return this.http.get<IBlogPost[]>(blog);
  }

  getConfigurations() {
    var configurationsData = [];
    this.http.get(this.configuration).subscribe(data => {
      configurationsData.push(data);
      console.log(data);
      // This will work and will print all the paths
    });

    //This will not work and will not print them, like if the collection is empty
    configurationsData.forEach(x => console.log(x));

    return configurationsData;
  }

我在哪里注入(inject)我的服务类:

blogs: IBlogPost[] = [];

  private blogsPaths: string[] = [];

  errorMessage = "";

  constructor(private appUtilityService: AppUtilityServices) {}

  ngOnInit() {
    //This will not work, blogsPaths will not received the full collection as it should
    this.blogsPaths = this.appUtilityService.getConfigurations();



    this.blogsPaths.forEach(blogPath =>
      this.appUtilityService.getBlogs(blogPath).subscribe(
        b =>
          b.forEach(blog => {
            this.blogs.push(blog);
          }),
        error => (this.errorMessage = <any>error)
      )
    );
  }

测试配置.json:

[
  "../../assets/BlogPosts/testBlog1.json",
  "../../assets/BlogPosts/testBlog2.json"
]

如果你提供了一个关于集合如何在 javascript 中工作以及如何正确返回它们的好教程，则奖励

Answer 1

原来是这样，是真的……

这里我做得很好:

初始化:

this.appUtilityService.getConfigurations().subscribe(
  b =>
    b.forEach(x => {
      this.appUtilityService.getBlogs(x).subscribe(
        b =>
          b.forEach(blog => {
            this.blogs.push(blog);
          }),
        error => (this.errorMessage = <any>error)
      );
    }),
  error => (this.errorMessage = <any>error)
);

应用程序服务:

  getBlogs(blog: string): Observable<IBlogPost[]> {
    return this.http.get<IBlogPost[]>(blog);
  }

  getConfigurations(): Observable<string[]> {
    return this.http.get<string[]>(this.configuration);
  }

让它变得非常漂亮:

  ngOnInit() {
    this.initializeBlog();
  }

  private initializeBlog(): void {
    this.appUtilityService.getConfigurations().subscribe(
      b =>
        b.forEach(x => {
          this.appUtilityService.getBlogs(x).subscribe(
            b =>
              b.forEach(blog => {
                this.blogs.push(blog);
              }),
            error => (this.errorMessage = <any>error)
          );
        }),
      error => (this.errorMessage = <any>error)
    );
  }