Update README.md (#36)

Author: geekhybrid

README.md

@@ -29,29 +29,33 @@ import 'vue3-tree-vue/dist/style.css'; // remember to add this in your component
   setup() {
     const onItemChecked = (checkedItems: TreeViewItem[]) => console.log(checkedItems);
     const onItemSelected = (item: TreeViewItem) => console.log(item);
-    const onBeforeItemDropped = (droppedItem: TreeViewItem, dropHost: TreeViewItem | undefined) => {
-      // dropHost == undefined means dropping at the root of the tree.
-      
-      // Here you can specify any kind of drop validation you will like.
-      // this function should return true if the drop operation is valid.
-
-      if (dropHost.type !== playlist) return false
-      return true;
+
+
+    // How to handle drag and drop logic
+    const onBeforeItemDropped = (droppedItem: TreeViewItem, destinationNode: TreeViewItem | undefined) => {
+          // destinationNode == undefined means dropping at the root of the tree.
+          
+          // Here you can specify any kind of drop validation you will like.
+          // this function should return true if the drop operation is valid.
+
+        return new Promise((resolve, _) => {
+          resolve(droppedItem !== destinationNode) // Replace this logic with your logic.
+        });
     }
     const onItemExpanded = (expandedItem: TreeViewItem) => {
-      //to use this feature properly you need to set lazyLoad property as true 
-      //fetch data
-      const lazyLoadedItems = fetchFromApi(...);
-      expandedItem.children.push(...lazyLoadedItems)
+          //to use this feature properly you need to set lazyLoad property as true 
+          //fetch data
+          const lazyLoadedItems = fetchFromApi(...);
+          expandedItem.children.push(...lazyLoadedItems)
     }
     const items = ref<TreeViewItem[]>([]); // define your tree items here.
 
     return {
-      onItemChecked,
-      onItemSelected,
-      onBeforeItemDropped,
-      onItemExpanded,
-      items
+          onItemChecked,
+          onItemSelected,
+          onBeforeItemDropped,
+          onItemExpanded,
+          items
     }
   }
 ```
@@ -121,4 +125,4 @@ export interface TreeViewItem {
 
 | Name | Description |
 | -------------|-------------
-| on-item-hover | Use in `child-append` and `item-append` slots to only show when the cursor is hovering on the node 
+| on-item-hover | Use in `child-append` and `item-append` slots to only show when the cursor is hovering on the node