element-plus/docs/en-US/component/tree-v2.md
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---
lang: en-US
---
# <ElBadge value="beta">Tree V2 virtualized tree</ElBadge>
Tree view with blazing fast scrolling performance for any amount of data
## Basic usage
Basic tree structure.
:::demo
tree-v2/basic
:::
## Selectable
Used for node selection.
:::demo
tree-v2/selectable
:::
## Disabled checkbox
The checkbox of a node can be set as disabled.
:::demo In the example, `disabled` property is declared in defaultProps, and some nodes are set as `disabled: true`. The corresponding checkboxes are disabled and can't be clicked.
tree-v2/disabled
:::
## Default expanded and default checked
Tree nodes can be initially expanded or checked
:::demo Use `default-expanded-keys` and `default-checked-keys` to set initially expanded and initially checked nodes respectively.
tree-v2/default-state
:::
## Custom node content
The content of tree nodes can be customized, so you can add icons or buttons as you will
:::demo
tree-v2/custom-node
:::
## Tree node filtering
Tree nodes can be filtered
:::demo Invoke the `filter` method of the Tree instance to filter tree nodes. Its parameter is the filtering keyword. Note that for it to work, `filter-node-method` is required, and its value is the filtering method.
tree-v2/filter
:::
## Attributes
| Attribute | Description | Type | Default |
| --------------------- | -------------------------------------------------------------------------------------------------------------------------------------------- | --------------------- | ------- |
| data | tree data | array | — |
| empty-text | text displayed when data is void | string | — |
| props | configuration options, see the following table | object | — |
| highlight-current | whether current node is highlighted | boolean | false |
| expand-on-click-node | whether to expand or collapse node when clicking on the node, if false, then expand or collapse node only when clicking on the arrow icon. | boolean | true |
| check-on-click-node | whether to check or uncheck node when clicking on the node, if false, the node can only be checked or unchecked by clicking on the checkbox. | boolean | false |
| default-expanded-keys | array of keys of initially expanded nodes | array | — |
| show-checkbox | whether node is selectable | boolean | false |
| check-strictly | whether checked state of a node not affects its father and child nodes when `show-checkbox` is `true` | boolean | false |
| default-checked-keys | array of keys of initially checked nodes | array | — |
| current-node-key | key of initially selected node | string, number | — |
| filter-method | this function will be executed on each node when use filter method. if return `false`, tree node will be hidden. | Function(value, data) | — |
| indent | horizontal indentation of nodes in adjacent levels in pixels | number | 16 |
| icon | custome tree node icon | string | - |
## props
| Attribute | Description | Type | Default |
| --------- | ------------------------------------------------------------------------------------ | -------------- | -------- |
| id | unique identity key name for nodes, its value should be unique across the whole tree | string, number | id |
| label | specify which key of node object is used as the node's label | string | label |
| children | specify which node object is used as the node's subtree | string | children |
| disabled | specify which key of node object represents if node's checkbox is disabled | boolean | disabled |
## Method
`Tree` has the following method, which returns the currently selected array of nodes.
| Method | Description | Parameters |
| --------------- | ---------------------------------------- | ---------------------------------------- |
| filter | filter all tree nodes, filtered nodes will be hidden | (query: string) |
| getCheckedNodes | If the node can be selected (`show-checkbox` is `true`), it returns the currently selected array of nodes | (leafOnly: boolean) |
| getCheckedKeys | If the node can be selected (`show-checkbox` is `true`), it returns the currently selected array of node's keys | (leafOnly: boolean) |
| setCheckedKeys | set certain nodes to be checked | (keys: TreeKey[]) |
| setChecked | set node to be checked or not | (key: TreeKey, checked: boolean) |
| getHalfCheckedNodes | If the node can be selected (`show-checkbox` is `true`), it returns the currently half selected array of nodes | - |
| getHalfCheckedKeys | If the node can be selected (`show-checkbox` is `true`), it returns the currently half selected array of node's keys | - |
| getCurrentKey | return the highlight node's key (undefined if no node is highlighted) | — |
| getCurrentNode | return the highlight node's data (undefined if no node is highlighted) | — |
| setCurrentKey | set highlighted node by key | (key: TreeKey) |
| setData | When the data is very large, using reactive data will cause the poor performance, so we provide a way to avoid this situation | (data: TreeData) |
## Events
| Event Name | Description | Parameters |
| ---------------- | ---------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------- |
| node-click | triggers when a node is clicked | (data: TreeNodeData, node: TreeNode) |
| node-contextmenu | triggers when a node is clicked by right button | (e: Event, data: TreeNodeData, node: TreeNode) |
| check-change | triggers when the selected state of the node changes | (data: TreeNodeData, checked: boolean) |
| check | triggers after clicking the checkbox of a node | (data: TreeNodeData, info: { checkedKeys: TreeKey[],checkedNodes: TreeData, halfCheckedKeys: TreeKey[], halfCheckedNodes: TreeData,}) |
| current-change | triggers when current node changes | (data: TreeNodeData, node: TreeNode) |
| node-expand | triggers when current node open | (data: TreeNodeData, node: TreeNode) |
| node-collapse | triggers when current node close | (data: TreeNodeData, node: TreeNode) |
## Slots
| Name | Description |
| ---- | -------------------------------------------------------------------------------------------- |
| — | Custom content for tree nodes. The scope parameter is { node: TreeNode, data: TreeNodeData } |