perf(ReplaySubject): little performance adjustments

src/ReplaySubject.ts

@@ -31,8 +31,13 @@ export class ReplaySubject<T> extends Subject<T> {
  }
 
  private nextInfiniteTimeWindow(value: T): void {
- this._events.push(value);
- this._trimBufferSize();
+ const _events = this._events;
+ _events.push(value);
+ // Since this method is invoked in every next() call than the buffer
+ // can overgrow the max size only by one item
+ if (_events.length > this._bufferSize) {
+ _events.shift();
+ }
 
  super.next(value);
  }
@@ -49,13 +54,12 @@ export class ReplaySubject<T> extends Subject<T> {
  const _infiniteTimeWindow = this._infiniteTimeWindow;
  const _events = _infiniteTimeWindow ? this._events : this._trimBufferThenGetEvents();
  const scheduler = this.scheduler;
+ const len = _events.length;
  let subscription: Subscription;
 
  if (this.closed) {
  throw new ObjectUnsubscribedError();
- } else if (this.hasError) {
- subscription = Subscription.EMPTY;
- } else if (this.isStopped) {
+ } else if (this.isStopped || this.hasError) {
  subscription = Subscription.EMPTY;
  } else {
  this.observers.push(subscriber);
@@ -66,7 +70,6 @@ export class ReplaySubject<T> extends Subject<T> {
  subscriber.add(subscriber = new ObserveOnSubscriber<T>(subscriber, scheduler));
  }
 
- const len = _events.length;
  if (_infiniteTimeWindow) {
  for (let i = 0; i < len && !subscriber.closed; i++) {
  subscriber.next(<T>_events[i]);
@@ -96,7 +99,7 @@ export class ReplaySubject<T> extends Subject<T> {
  const _windowTime = this._windowTime;
  const _events = <ReplayEvent<T>[]>this._events;
 
- let eventsCount = _events.length;
+ const eventsCount = _events.length;
  let spliceCount = 0;
 
  // Trim events that fall out of the time window.
@@ -120,14 +123,6 @@ export class ReplaySubject<T> extends Subject<T> {
  return _events;
  }
 
- private _trimBufferSize(): void {
- const { _events } = this;
-
- for (let i = 0; i < _events.length - this._bufferSize; i++) {
- _events.shift();
- }
- }
-
 }
 
 class ReplayEvent<T> {