D3.js collapsibleRRR tree with refined boxes/links
This example shows a collapsible tree visualization built with D3.js v3, displaying hierarchical data as colored rectangular nodes connected by labeled links. The code uses `d3.layout.tree` to position nodes, and implements interactive collapsing/expanding on click with smooth transitions. Rendering is done via SVG, with node colors mapped from data types, tooltips, and zoom/drag behavior provided through `d3.behavior.zoom`. The data is loaded from a JSON file containing nested node objects with name, type, and link direction attributes.