Function onDragLeave

packages/react-aria/src/dnd/useDrop.ts:280–314

(e: DragEvent)

  };

  let onDragLeave = (e: DragEvent) => {
    e.preventDefault();
    e.stopPropagation();

    // We would use e.relatedTarget to detect if the drag is still inside the drop target,
    // but it is always null in WebKit. https://bugs.webkit.org/show_bug.cgi?id=66547
    // Instead, we track all of the targets of dragenter events in a set, and remove them
    // in dragleave. When the set becomes empty, we've left the drop target completely.
    // We must also remove any elements that are no longer in the DOM, because dragleave
    // events will never be fired for these. This can happen, for example, with drop
    // indicators between items, which disappear when the drop target changes.

    let target = getEventTarget(e);
    state.dragOverElements.delete(target);

    // Only remove stale elements when leaving the drop target itself.
    // Avoids issues with portal children bubbling dragleave events through the React tree.
    if (target === e.currentTarget) {
      for (let element of state.dragOverElements) {
        if (!nodeContains(e.currentTarget, element)) {
          state.dragOverElements.delete(element);
        }
      }
    }

    if (state.dragOverElements.size > 0) {
      return;
    }

    if (state.dropEffect !== 'none') {
      fireDropExit(e);
    }

    clearTimeout(state.dropActivateTimer);
  };

  let onDrop = (e: DragEvent) => {
    e.preventDefault();