TreeNode: Tree node

In termr: Modern Reactive Terminal Applications with Data Workflows

Tree node

Description

A node of a tree shown by tree_view(). See tree_node().

Public fields

label

Text shown for the node.

data

Any R value attached to the node.

id

Optional identifier.

loader

NULL or ⁠function(node)⁠ returning children, called the first time the node is expanded.

loaded

Has the loader run?

Active bindings

parent

The parent node (read-only).

children

Child nodes (read-only).

expanded

Is the node expanded? (assign to expand / collapse)

Methods

Public methods

• TreeNode$new()

• TreeNode$add()

• TreeNode$remove()

• TreeNode$clear()

• TreeNode$expand()

• TreeNode$collapse()

• TreeNode$toggle()

• TreeNode$expandable()

• TreeNode$depth()

• TreeNode$ancestors()

• TreeNode$path()

• TreeNode$walk()

• TreeNode$find()

• TreeNode$changed()

• TreeNode$print()

• TreeNode$clone()

---

TreeNode$new()

Create a node. See tree_node().

Usage

TreeNode$new(
  label,
  children = list(),
  data = NULL,
  expanded = FALSE,
  id = NULL,
  loader = NULL
)

Arguments

label

Label.

children

Child nodes (or labels).

data

Attached value.

expanded

Start expanded?

id

Identifier.

loader

Lazy loader.

---

TreeNode$add()

Add a child.

Usage

TreeNode$add(node, data = NULL, expanded = FALSE)

Arguments

node

A TreeNode or a label.

data

Data for a node created from a label.

expanded

Expanded state for a node created from a label.

Returns

The child node.

---

TreeNode$remove()

Detach the node from its parent.

Usage

TreeNode$remove()

---

TreeNode$clear()

Remove all children.

Usage

TreeNode$clear()

---

TreeNode$expand()

Expand the node (running the loader if needed).

Usage

TreeNode$expand()

---

TreeNode$collapse()

Collapse the node.

Usage

TreeNode$collapse()

---

TreeNode$toggle()

Toggle between expanded and collapsed.

Usage

TreeNode$toggle()

---

TreeNode$expandable()

Can the node be expanded?

Usage

TreeNode$expandable()

---

TreeNode$depth()

Depth below the root (the root is 0).

Usage

TreeNode$depth()

---

TreeNode$ancestors()

Parent, grandparent, ... up to the root.

Usage

TreeNode$ancestors()

---

TreeNode$path()

Labels from the root to this node.

Usage

TreeNode$path()

---

TreeNode$walk()

This node and all descendants (depth first).

Usage

TreeNode$walk()

---

TreeNode$find()

Find a descendant by id.

Usage

TreeNode$find(id)

Arguments

id

Identifier.

---

TreeNode$changed()

Notify the tree view that the node changed.

Usage

TreeNode$changed()

---

TreeNode$print()

Print the subtree.

Usage

TreeNode$print(...)

Arguments

...

Ignored.

---

TreeNode$clone()

The objects of this class are cloneable with this method.

Usage

TreeNode$clone(deep = FALSE)

Arguments

deep

Whether to make a deep clone.

termr documentation built on Oct. 21, 2026, 5:13 p.m.