请问一下，序列号为什么显示不了？

export class LifeComponent implements OnInit,OnChanges,DoCheck,AfterContentInit,AfterContentChecked,AfterViewInit,AfterViewChecked,OnDestroy{

  @Input()

  name:string;

  logIt(msg:string){

    console.log('#${logIndex++} ${msg}');

  }

  constructor() {

    this.logIt("name属性在constructor里的值是："+name);

  }

  ngOnInit() {

    this.logIt("ngOnInit");

  }

  ngOnChanges(changes: SimpleChanges): void {

    let name = changes['name'].currentValue;

    this.logIt("name属性在constructor里的值是：" + name);

  }

  ngDoCheck(): void {

    this.logIt("ngDoCheck");

  }

  ngAfterContentInit(): void {

    this.logIt("ngAfterContentInit");

  }

  ngAfterContentChecked(): void {

    this.logIt("ngAfterContentChecked");

  }

  ngAfterViewInit(): void {

    this.logIt("ngAfterViewInit");

  }

  ngAfterViewChecked(): void {

    this.logIt("ngAfterViewChecked");

  }

  ngOnDestroy(): void {

    this.logIt("ngOnDestroy");

  }

}