Handles logical direction mapping (LR, RL, TB, BT, H, V) to actual layout transformations. Isolates the complexity of flipping, splitting, and combining layouts based on direction. Demonstrates clean separation of concerns by decoupling directional logic from core layout algorithms. An engineer could extract this module by replacing the separateTree import and adapting the HierarchyNode/HierarchyOptions interfaces to their tree structure.

Splits a tree hierarchy into left and right subtrees for horizontal/vertical layouts that require bifurcated processing. Implements a clean, focused algorithm with configurable side assignment. Shows strong encapsulation of a common tree operation. To reuse, one would need to provide a hierarchy function matching the expected signature (data, options, isolated) => HierarchyNode, which is a standard tree-building pattern.

Provides the core Node class and hierarchy-building functionality that all layout algorithms depend on. Includes useful methods for tree traversal (DFTraverse, BFTraverse), bounding box calculation, and geometric transformations (translate, right2left, bottom2top). The Node class implements standard tree node behavior with layout-specific enhancements like gap handling. Extractable by adapting the HierarchyData/HierarchyOptions interfaces and the assign utility, yielding a reusable tree construction library with rich node APIs.