Question

据我了解Angular 2服务，如果您在根组件中注入一个，则所有子组件共享该服务的相同实例。

我有一个我想在装饰器和应用程序中使用的日志记录服务。但我想重用根组件中的现有服务实例。

现在，如果我在日志服务构造函数中放置一个调试器语句，我的服务会被多次实例化。我使用ReflectiveInjector，但我认为它创建了一个新实例，而不是使用全局实例。

也许我正在犯这个错误，或者我缺乏理解。我这样做的原因是因为我在日志记录服务中有一个可观察的流，并且多个实例创建了多个observable。

@Injectable()
export class LoggerService {

    private _applicationLog$: ReplaySubject<string>;
    get applicationLog$(): Observable<string> {
        return this._applicationLog$.asObservable();
    }

    constructor(private $localStorage: LocalStorageService, private $appSettings: AppSettings) {
        this._applicationLog$ = <ReplaySubject<string>>new ReplaySubject();
    }

    log(s: string){
       //log to a file and push into the stream
       this._applicationLog$.next(s);
    }
}

现在这是我的日志装饰器

var injector = ReflectiveInjector.resolveAndCreate([LocalStorageService, AppSettings]);
var service = <LoggerService>injector.resolveAndInstantiate(LoggerService);
var appSettings = <AppSettings>injector.resolveAndInstantiate(AppSettings);

function getTime() {
    let now = new Date();
    let min = ("00" + now.getMinutes()).substr(-2, 2);
    let hours = ("00" + now.getHours()).substr(-2, 2);
    return `${hours}:${min}`;
}

function log(message) {
    service.log(`[${getTime()}] ${message}`);
}

export function Trace() {
    return function (target: any, propertyKey: string, descriptor: PropertyDescriptor) {
        if (AppSettings.logSeverity !== LogSeverity.Trace) return;
        log(`TRACE ${propertyKey}.enter()`);
    };
}

现在我有一个阅读日志的组件

@Component({
    templateUrl: 'applicationlogs.template.html'
})
export class ApplicationLogsPage implements OnInit {
    logs: string[];
    private subscription: Observable<string>;
    constructor(private navCtrl: NavController, private $loggerService: LoggerService) { }

    ngOnInit(){
        this.subscription = this.$loggerService.applicationLog$.subscribe((s) => {
            this.logs = s.split(/\r\n|\r|\n/g);
        });
    }
}

如何在Angular 2应用程序模块和装饰器之间共享服务实例？

0 个答案: