A Simple vue3 project for rendering items in a tree.

npm i vue3-tree-vue

<template>    
    <vue3-tree-vue :items="items" 
                   :isCheckable="false"  //Set to true if you want to get checkable items
                   :hideGuideLines="false"
                   @onCheck="onItemChecked"
                   @dropValidator="onBeforeItemDropped"
                   @onSelect="onItemSelected"
                   @onExpand="onItemExpanded"
                   >
      <!-- Applying some simple styling to tree-items -->
       <template v-slot:item-prepend-icon="treeViewItem" >
              <img src="./assets/folder.svg"
                   alt="folder"
                   v-if="treeViewItem.type === 'folder'"
                   height="20" width="20" />
       </template>
    </vue3-tree-vue>
</template>

import 'vue3-tree-vue/dist/style.css'; // remember to add this in your component or maint.[ts/js]
 
  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;
    }
    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)
    }
    const items = ref<TreeViewItem[]>([]); // define your tree items here.
    
    return {
      onItemChecked,
      onItemSelected,
      onBeforeItemDropped,
      onItemExpanded,
      items
    }
  }

Selectable Tree Items

Checkable Tree Items

Drag and Drop

Properties of the TreeView

Property	Default	Description
items	Empty array	An array of TreeViewItem.
hideGuideLines	false	Determines the visibility of the guidelines
lazyLoad	false	Determines if the tree supports lazy-loading
isCheckable	false	Defines if items can be selected (one at a time) or selected (using a checkbox)
checkboxStyle	undefined	Defines the style to be applied to the checkboxes on the tree.
dropValidator	undefined	Specifies a callback of drag and drop rules.

Basic properties of each tree-node.

export interface TreeViewItem {
  name: string;
  id?: string | number;
  children?: TreeViewItem[];
  checked?: boolean;
  selected?: boolean;
  expanded?: boolean;
  disabled?: boolean;// When disabled, an item can neither be selected nor checked
  meta?: any;// provides meta-data of any type per node.
}

Event Handlers

Events	Description
onSelect	Callback function when an item is selected from the tree .Returns an ItemEventArgs.
onCheck	Callback function when an item is checked/unchecked from the tree.
onExpand	Callback function when an item is expanded (Can be used for lazy-loading)
onCollapse	Callback function when an item is collapsed

The `onCheck` event may be fired more than once to show the change in state of deep hierachies.

Styles

Class	Description
selected-tree-item	Defines the style for the selectedItem

Slots

Name	Description
item-prepend-icon	Defines the node's prepend icon.
item-prepend	Defines a slot to house content before the node's label.
item-expander	Defines a slot for custom expander implementations
item-append	Defines a slot for adding custom content after the item name
child-append	Defines a slot for adding a custom item after the last child

Classes

Name	Description
on-item-hover	Use in child-append and item-append slots to only show when the cursor is hovering on the node