part-of-circuit-breaker.js

...
private interceptErrorResponse(error: any) {
  const shouldCircuitBreakerBeOpen = this.errorHandler(error);

  if (shouldCircuitBreakerBeOpen && !this.isOpen) {
    this.openCircuitBreaker();
  }

  return Promise.reject(error);
}

private openCircuitBreaker() {
  this.isOpen = true;

  setTimeout(() => {
    this.isOpen = false;
  }, this.timeout);
}
...