fix(Subscriber): creates subscriber throwable by default

- closes #2813

src/Subscriber.ts

@@ -39,7 +39,7 @@ export class Subscriber<T> extends Subscription implements Observer<T> {
 
  public syncErrorValue: any = null;
  public syncErrorThrown: boolean = false;
- public syncErrorThrowable: boolean = false;
+ public syncErrorThrowable: boolean = true;
 
  protected isStopped: boolean = false;
  protected destination: PartialObserver<any>; // this `any` is the escape hatch to erase extra type param (e.g. R)
@@ -60,24 +60,24 @@ export class Subscriber<T> extends Subscription implements Observer<T> {
  switch (arguments.length) {
  case 0:
  this.destination = emptyObserver;
+ this.syncErrorThrowable = false;
  break;
  case 1:
  if (!destinationOrNext) {
  this.destination = emptyObserver;
+ this.syncErrorThrowable = false;
  break;
  }
  if (typeof destinationOrNext === 'object') {
  if (destinationOrNext instanceof Subscriber) {
  this.destination = (<Subscriber<any>> destinationOrNext);
  (<any> this.destination).add(this);
  } else {
- this.syncErrorThrowable = true;
  this.destination = new SafeSubscriber<T>(this, <PartialObserver<any>> destinationOrNext);
  }
  break;
  }
  default:
- this.syncErrorThrowable = true;
  this.destination = new SafeSubscriber<T>(this, <((value: T) => void)> destinationOrNext, error, complete);
  break;
  }