ApplicationRef.isStable未执行

Question

我正在尝试编写一个服务来衡量应用程序变得稳定的完成时间。以下是该服务：

measure.service.ts

import { ApplicationRef, Injectable } from "@angular/core";
import { first, map } from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class MeasureService {
  public constructor(private readonly applicationRef: ApplicationRef) { }

  public measure(): void {
    const startTime = Date.now();

    console.log(startTime);
    /**
     * Test stability metrics of application.
     */
    this.applicationRef.isStable.pipe(
      first(isStable => isStable),
      map(() => {
        /* tslint:disable-next-line:no-console */
        console.log("App stable ("+ Math.round((Date.now() - startTime) / 1000) + " secs)");
      })
    );
  }
}

app.module.ts (缩写)：

...
@NgModule({
   providers: [
      MeasureService
   ]
})

root.component.ts

import { Component, OnInit } from "@angular/core";
import { MeasureService } from "../application-insights/measure.service";

@Component({
  selector: "mr-root",
  template: `
    <router-outlet></router-outlet>
  `,
})
export class RootComponent implements OnInit {
  public constructor(
    private readonly measureService: MeasureService
  ) {  
    this.measureService.measure();    
  }

  public ngOnInit(): void {
  }
}

MeasureService的第一个console.log正确地记录了时间。但是，看起来applicationRef.isStable从不触发，因此，第二个console.log永远不会写入控制台。

我做得对吗，还是我漏掉了什么？

Answer 1

measure.service.ts (更新)：

import { ApplicationRef, Injectable } from "@angular/core";
import { first } from 'rxjs/operators';

@Injectable({
  providedIn: 'root'
})
export class MeasureService {
  public constructor(private readonly applicationRef: ApplicationRef) { }

  public measure(): void {
    const startTime = Date.now();

    /**
     * Test stability metrics of application.
     */
    this.applicationRef.isStable.pipe(
      first(isStable => isStable)
    ).subscribe(() => {
      /* tslint:disable-next-line:no-console */
      console.log("App stable ("+ Math.round((Date.now() - startTime) / 1000) + " secs)");
    });
  }
}