I am a Computer Scientist and Musician by training. A writer with interests in Philosophy, Economics, Technology, Politics, Business, the Arts and Fiction.
Published
Edited
Aug 31, 2020
md`# Tree View`
{
const data = await FileAttachment("flare-2.json").json();
return drawTreeView(data);
}
d3 = require('d3@6')
import { addDefaults } from '@nuuuwan/option-utils'
function drawTreeView(data, options) {
options = addDefaults(options, {
width: 900,
margin: { top: 10, right: 120, bottom: 10, left: 40 }
});
options = addDefaults(options, {
dx: 10,
dy: options.width / 6
});
const root = d3.hierarchy(data);
const tree = d3.tree().nodeSize([options.dx, options.dy]);
root.x0 = options.dy / 2;
root.y0 = 0;
root.descendants().forEach((d, i) => {
d.id = i;
d._children = d.children;
if (d.depth && d.data.name.length !== 7) d.children = null;
});
const svg = d3
.create("svg")
.attr("viewBox", [
-options.margin.left,
-options.margin.top,
options.width,
options.dx
])
.style("font", "10px sans-serif")
.style("user-select", "none");
const gLink = svg
.append("g")
.attr("fill", "none")
.attr("stroke", "#555")
.attr("stroke-opacity", 0.4)
.attr("stroke-width", 1.5);
const gNode = svg
.append("g")
.attr("cursor", "pointer")
.attr("pointer-events", "all");
function update(source) {
const duration = d3.event && d3.event.altKey ? 2500 : 250;
const nodes = root.descendants().reverse();
const links = root.links();
// Compute the new tree layout.
tree(root);
let left = root;
let right = root;
root.eachBefore(node => {
if (node.x < left.x) left = node;
if (node.x > right.x) right = node;
});
const height =
right.x - left.x + options.margin.top + options.margin.bottom;
const diagonal = d3
.linkHorizontal()
.x(d => d.y)
.y(d => d.x);
const transition = svg
.transition()
.duration(duration)
.attr("viewBox", [
-options.margin.left,
left.x - options.margin.top,
options.width,
height
])
.tween(
"resize",
window.ResizeObserver ? null : () => () => svg.dispatch("toggle")
);
// Update the nodes…
const node = gNode.selectAll("g").data(nodes, d => d.id);
// Enter any new nodes at the parent's previous position.
const nodeEnter = node
.enter()
.append("g")
.attr("transform", d => `translate(${source.y0},${source.x0})`)
.attr("fill-opacity", 0)
.attr("stroke-opacity", 0)
.on("click", (event, d) => {
d.children = d.children ? null : d._children;
update(d);
});
nodeEnter
.append("circle")
.attr("r", 2.5)
.attr("fill", d => (d._children ? "#555" : "#999"))
.attr("stroke-width", 10);
nodeEnter
.append("text")
.attr("dy", "0.31em")
.attr("x", d => (d._children ? -6 : 6))
.attr("text-anchor", d => (d._children ? "end" : "start"))
.text(d => d.data.name)
.clone(true)
.lower()
.attr("stroke-linejoin", "round")
.attr("stroke-width", 3)
.attr("stroke", "white");
// Transition nodes to their new position.
const nodeUpdate = node
.merge(nodeEnter)
.transition(transition)
.attr("transform", d => `translate(${d.y},${d.x})`)
.attr("fill-opacity", 1)
.attr("stroke-opacity", 1);
// Transition exiting nodes to the parent's new position.
const nodeExit = node
.exit()
.transition(transition)
.remove()
.attr("transform", d => `translate(${source.y},${source.x})`)
.attr("fill-opacity", 0)
.attr("stroke-opacity", 0);
// Update the links…
const link = gLink.selectAll("path").data(links, d => d.target.id);
// Enter any new links at the parent's previous position.
const linkEnter = link
.enter()
.append("path")
.attr("d", d => {
const o = { x: source.x0, y: source.y0 };
return diagonal({ source: o, target: o });
});
// Transition links to their new position.
link
.merge(linkEnter)
.transition(transition)
.attr("d", diagonal);
// Transition exiting nodes to the parent's new position.
link
.exit()
.transition(transition)
.remove()
.attr("d", d => {
const o = { x: source.x, y: source.y };
return diagonal({ source: o, target: o });
});
// Stash the old positions for transition.
root.eachBefore(d => {
d.x0 = d.x;
d.y0 = d.y;
});
}
update(root);
return svg.node();
}
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
