Update (Angular 6 +) The recommended way to create a singleton service has changed. It is now recommended to specify in the @Injectable decorator on the service that it should be provided in the ‘root’. This makes a lot of sense to me and there’s no need to list all the provided services in your … Read more
You need to use method Array.filter: this.persons = this.personService.getPersons().filter(x => x.id == this.personId)[0]; or Array.find this.persons = this.personService.getPersons().find(x => x.id == this.personId);
update If you use the router you can use lifecycle hooks or resolvers to delay navigation until the data arrived. https://angular.io/guide/router#milestone-5-route-guards To load data before the initial rendering of the root component APP_INITIALIZER can be used How to pass parameters rendered from backend to angular2 bootstrap method original When console.log(this.ev) is executed after this.fetchEvent();, this … Read more
TL;DR: No, don’t subscribe manually to them, don’t use them in services. Use them as is shown in the documentation only to emit events in components. Don’t defeat angular’s abstraction. Answer: No, you should not subscribe manually to it. EventEmitter is an angular2 abstraction and its only purpose is to emit events in components. Quoting … Read more
EDIT: as of 2021, the proper way is to use the shareReplay operator natively proposed by RxJs. See more details in below answers. Cache the data and if available cached, return this otherwise make the HTTP request. import {Injectable} from ‘@angular/core’; import {Http, Headers} from ‘@angular/http’; import {Observable} from ‘rxjs/Observable’; import ‘rxjs/add/observable/of’; //proper way to … Read more