When I assign getEvent() type to IEvent, I get this error,

TS2322: Type 'IEvent | undefined' is not assignable to type 'IEvent'.

import { Injectable } from "@angular/core"
import { Subject, Observable } from "rxjs"
import { IEvent } from "./event.model"

@Injectable()
export class EventService {
  getEvents():Observable<IEvent[]> {
    let subject = new Subject<IEvent[]>()

    setTimeout(() => { subject.next(EVENTS); subject.complete() }, 200)
    return subject
  }

  getEvent(id: number): IEvent {
    return EVENTS.find(event => event.id === id) // Error here
  }
}  

CodePudding user response：

Add 'undefined' to your return type:

  getEvent(id: number): IEvent | undefined {
    return EVENTS.find(event => event.id === id) // Error here
  }

CodePudding user response：

Define the IEvent type as "any". If that doesn't fix your issue try upgrading your rxjs version. This should fix your problem!