Angular 调用服务逻辑

projects = [
    {
      id: 1,
      name: "企业协作平台",
      desc: "这是一个企业内部项目",
      coverImg: "assets/images/covers/0.jpg"
    },
    {
      id: 2,
      name: "自动化测试项目",
      desc: "这是一个企业内部项目",
      coverImg: "assets/images/covers/1.jpg"
    }
  ];

constructor(private dialog: MatDialog,
    private cd: ChangeDetectorRef,
    private projectService: ProjectService) {
    this.projectService.get("37489e0c-df34-c261-71c4-ce75357e3035").subscribe(projects => this.projects = projects);
  }

private getThumbnails() {
    return _.range(0, 40).map(i => `/assets/img/covers/${i}_tn.jpg`);
  }

this.projectService.get("37489e0c-df34-c261-71c4-ce75357e3035").subscribe(
      projects => {
        this.projects = projects;
        this.cd.markForCheck();
      }
    );

    dialogRef.afterClosed().subscribe((project) => {
      if (!project) return;
      this.projectService.add(project);
      this.cd.markForCheck();
    });

dialogRef.afterClosed().pipe(filter(n => n)).subscribe((project) => {
      this.projectService.add(project);
      this.cd.markForCheck();
    });

 dialogRef.afterClosed()
      .pipe(
        filter(n => n),
        switchMap(v => this.projectService.add(v)))
      .subscribe(project => console.log(project));