Function dispatchEvent

docs/external/js/react-dom.development.js:4298–4338

(topLevelType, eventSystemFlags, container, nativeEvent)

  }

  function dispatchEvent(topLevelType, eventSystemFlags, container, nativeEvent) {
    if (!_enabled) {
      return;
    }

    if (hasQueuedDiscreteEvents() && isReplayableDiscreteEvent(topLevelType)) {
      // If we already have a queue of discrete events, and this is another discrete
      // event, then we can't dispatch it regardless of its target, since they
      // need to dispatch in order.
      queueDiscreteEvent(null, // Flags that we're not actually blocked on anything as far as we know.
      topLevelType, eventSystemFlags, container, nativeEvent);
      return;
    }

    var blockedOn = attemptToDispatchEvent(topLevelType, eventSystemFlags, container, nativeEvent);

    if (blockedOn === null) {
      // We successfully dispatched this event.
      clearIfContinuousEvent(topLevelType, nativeEvent);
      return;
    }

    if (isReplayableDiscreteEvent(topLevelType)) {
      // This this to be replayed later once the target is available.
      queueDiscreteEvent(blockedOn, topLevelType, eventSystemFlags, container, nativeEvent);
      return;
    }

    if (queueIfContinuousEvent(blockedOn, topLevelType, eventSystemFlags, container, nativeEvent)) {
      return;
    } // We need to clear only if we didn't queue because
    // queueing is accummulative.


    clearIfContinuousEvent(topLevelType, nativeEvent); // This is not replayable so we'll invoke it but without a target,
    // in case the event system needs to trace it.

    {
      dispatchEventForLegacyPluginEventSystem(topLevelType, eventSystemFlags, nativeEvent, null);
    }
  } // Attempt dispatching an event. Returns a SuspenseInstance or Container if it's blocked.

  function attemptToDispatchEvent(topLevelType, eventSystemFlags, container, nativeEvent) {
    // TODO: Warn if _enabled is false.