The throttle operator returns an instance of the Observable that only emits one item from the upstream during the sequential time window that has passed. The throttle is a family of methods, such as throttleFirst or throttleLast.
The following diagram shows how the throttleFirst method works:
The throttleLast method works as follows:
The preceding diagrams shows that the throttleFirst and throttleLast methods can be used to reduce the emitted values.