当我在订阅者中获得某个值时，我正试图返回一个observable，但我失败了。
这是代码：
canActivate(route: ActivatedRouteSnapshot,state: RouterStateSnapshot):Observable<boolean> {
// get route to be activated
this.routeToActivate = route.routeConfig.path;
// get user access levels
return this._firebase.isUserAdmin <-- returns Subscription,not Observable
.map(user => user.access_level)
.subscribe( access => {
// I need to return an observable here
});
}
角度2中的可观察量资源不多，所以我不知道从哪里开始。有人可以帮忙吗？
更新 – >工作版
canActivate(route: ActivatedRouteSnapshot,state: RouterStateSnapshot):Observable<boolean> {
// get route to be activated
this.routeToActivate = route.routeConfig.path;
// get user access levels
return this._firebase.isUserAdmin
.map(user => {
let accessLevel = user.access_level;
if (accessLevel === 'admin' ) {
return true;
}
}).first();
}
您无法从订阅返回observable，但如果您使用map而不是subscribe，则返回Observable。
canActivate(route: ActivatedRouteSnapshot,state: RouterStateSnapshot):Observable<boolean> {
// get route to be activated
this.routeToActivate = route.routeConfig.path;
// get user access levels
return this._firebase.isUserAdminObservable
.map(user => {
// do something here
// user.access_level;
return true;
})
.first(); // for the observable to complete on the first event (usually required for `canActivate`)
// first needs to be imported like `map`,...
}
canActivate(route: ActivatedRouteSnapshot,state: RouterStateSnapshot):Observable<boolean> {
// get route to be activated
this.routeToActivate = route.routeConfig.path;
let subject = new Subject();
// get user access levels
this._firebase.isUserAdminObservable
.map(user => {
let accessLevel = user.access_level;
if (accessLevel === 'admin' ) {
subject.emit(true);
subject.complete();
}
return user;
});
return subject;
}
