Function attemptToDispatchEvent

docs/external/js/react-dom.development.js:4340–4395

(topLevelType, eventSystemFlags, container, nativeEvent)

  } // 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.
    var nativeEventTarget = getEventTarget(nativeEvent);
    var targetInst = getClosestInstanceFromNode(nativeEventTarget);

    if (targetInst !== null) {
      var nearestMounted = getNearestMountedFiber(targetInst);

      if (nearestMounted === null) {
        // This tree has been unmounted already. Dispatch without a target.
        targetInst = null;
      } else {
        var tag = nearestMounted.tag;

        if (tag === SuspenseComponent) {
          var instance = getSuspenseInstanceFromFiber(nearestMounted);

          if (instance !== null) {
            // Queue the event to be replayed later. Abort dispatching since we
            // don't want this event dispatched twice through the event system.
            // TODO: If this is the first discrete event in the queue. Schedule an increased
            // priority for this boundary.
            return instance;
          } // This shouldn't happen, something went wrong but to avoid blocking
          // the whole system, dispatch the event without a target.
          // TODO: Warn.


          targetInst = null;
        } else if (tag === HostRoot) {
          var root = nearestMounted.stateNode;

          if (root.hydrate) {
            // If this happens during a replay something went wrong and it might block
            // the whole system.
            return getContainerFromFiber(nearestMounted);
          }

          targetInst = null;
        } else if (nearestMounted !== targetInst) {
          // If we get an event (ex: img onload) before committing that
          // component's mount, ignore it for now (that is, treat it as if it was an
          // event on a non-React tree). We might also consider queueing events and
          // dispatching them after the mount.
          targetInst = null;
        }
      }
    }

    {
      dispatchEventForLegacyPluginEventSystem(topLevelType, eventSystemFlags, nativeEvent, targetInst);
    } // We're not blocked on anything.


    return null;
  }

  // List derived from Gecko source code: