quartz-research-note/assets/js/graph.js
Claudio Yanes 7e0f2e4449 Fix fetchData
The fetchData function suffer from a race condition. If the function is
called before the promise finishes, it will result in another pair of
HTTP request. This does not only make the function useless but
Actually, it makes it harmful as the data might be redownloaded twice.

Now fetchData is not a function but rather the promise by itself.
Previous callers are expected to await the variable instead, this
should be not concern as awaiting a promise multiple time in
JavaScript is completely safe.
2022-03-04 02:25:30 +00:00

221 lines
6.7 KiB
JavaScript

async function drawGraph(url, baseUrl, pathColors, depth, enableDrag, enableLegend, enableZoom) {
const { index, links, content } = await fetchData
const curPage = url.replace(baseUrl, "")
const parseIdsFromLinks = (links) => [...(new Set(links.flatMap(link => ([link.source, link.target]))))]
const neighbours = new Set()
const wl = [curPage || "/", "__SENTINEL"]
if (depth >= 0) {
while (depth >= 0 && wl.length > 0) {
// compute neighbours
const cur = wl.shift()
if (cur === "__SENTINEL") {
depth--
wl.push("__SENTINEL")
} else {
neighbours.add(cur)
const outgoing = index.links[cur] || []
const incoming = index.backlinks[cur] || []
wl.push(...outgoing.map(l => l.target), ...incoming.map(l => l.source))
}
}
} else {
parseIdsFromLinks(links).forEach(id => neighbours.add(id))
}
const data = {
nodes: [...neighbours].map(id => ({id})),
links: links.filter(l => neighbours.has(l.source) && neighbours.has(l.target)),
}
const color = (d) => {
if (d.id === curPage || (d.id === "/" && curPage === "")) {
return "var(--g-node-active)"
}
for (const pathColor of pathColors) {
const path = Object.keys(pathColor)[0]
const colour = pathColor[path]
if (d.id.startsWith(path)) {
return colour
}
}
return "var(--g-node)"
}
const drag = simulation => {
function dragstarted(event, d) {
if (!event.active) simulation.alphaTarget(1).restart();
d.fx = d.x;
d.fy = d.y;
}
function dragged(event,d) {
d.fx = event.x;
d.fy = event.y;
}
function dragended(event,d) {
if (!event.active) simulation.alphaTarget(0);
d.fx = null;
d.fy = null;
}
const noop = () => {}
return d3.drag()
.on("start", enableDrag ? dragstarted : noop)
.on("drag", enableDrag ? dragged : noop)
.on("end", enableDrag ? dragended : noop);
}
const height = 250
const width = document.getElementById("graph-container").offsetWidth
const simulation = d3.forceSimulation(data.nodes)
.force("charge", d3.forceManyBody().strength(-30))
.force("link", d3.forceLink(data.links).id(d => d.id))
.force("center", d3.forceCenter());
const svg = d3.select('#graph-container')
.append('svg')
.attr('width', width)
.attr('height', height)
.attr("viewBox", [-width / 2, -height / 2, width, height]);
if (enableLegend) {
const legend = [
{"Current": "var(--g-node-active)"},
{"Note": "var(--g-node)"},
...pathColors
]
legend.forEach((legendEntry, i) => {
const key = Object.keys(legendEntry)[0]
const colour = legendEntry[key]
svg.append("circle").attr("cx", -width/2 + 20).attr("cy", height/2 - 30 * (i+1)).attr("r", 6).style("fill", colour)
svg.append("text").attr("x", -width/2 + 40).attr("y", height/2 - 30 * (i+1)).text(key).style("font-size", "15px").attr("alignment-baseline","middle")
})
}
// draw links between nodes
const link = svg.append("g")
.selectAll("line")
.data(data.links)
.join("line")
.attr("class", "link")
.attr("stroke", "var(--g-link)")
.attr("stroke-width", 2)
.attr("data-source", d => d.source.id)
.attr("data-target", d => d.target.id)
// svg groups
const graphNode = svg.append("g")
.selectAll("g")
.data(data.nodes)
.enter().append("g")
// draw individual nodes
const node = graphNode.append("circle")
.attr("class", "node")
.attr("id", (d) => d.id)
.attr("r", (d) => {
const numOut = index.links[d.id]?.length || 0
const numIn = index.backlinks[d.id]?.length || 0
return 3 + (numOut + numIn) / 4
})
.attr("fill", color)
.style("cursor", "pointer")
.on("click", (_, d) => {
window.location.href = baseUrl + '/' + decodeURI(d.id).replace(/\s+/g, '-')
})
.on("mouseover", function (_, d) {
d3.selectAll(".node")
.transition()
.duration(100)
.attr("fill", "var(--g-node-inactive)")
const neighbours = parseIdsFromLinks([...(index.links[d.id] || []), ...(index.backlinks[d.id] || [])])
const neighbourNodes = d3.selectAll(".node").filter(d => neighbours.includes(d.id))
const currentId = d.id
const linkNodes = d3.selectAll(".link").filter(d => d.source.id === currentId || d.target.id === currentId)
// highlight neighbour nodes
neighbourNodes
.transition()
.duration(200)
.attr("fill", color)
// highlight links
linkNodes
.transition()
.duration(200)
.attr("stroke", "var(--g-link-active)")
// show text for self
d3.select(this.parentNode)
.select("text")
.raise()
.transition()
.duration(200)
.style("opacity", 1)
}).on("mouseleave", function (_,d) {
d3.selectAll(".node")
.transition()
.duration(200)
.attr("fill", color)
const currentId = d.id
const linkNodes = d3.selectAll(".link").filter(d => d.source.id === currentId || d.target.id === currentId)
linkNodes
.transition()
.duration(200)
.attr("stroke", "var(--g-link)")
d3.select(this.parentNode)
.select("text")
.transition()
.duration(200)
.style("opacity", 0)
})
.call(drag(simulation));
// draw labels
const labels = graphNode.append("text")
.attr("dx", 12)
.attr("dy", ".35em")
.text((d) => content[decodeURI(d.id).replace(/\s+/g, '-')]?.title || "Untitled")
.style("opacity", 0)
.style("pointer-events", "none")
.call(drag(simulation));
// set panning
if (enableZoom) {
svg.call(d3.zoom()
.extent([[0, 0], [width, height]])
.scaleExtent([0.25, 4])
.on("zoom", ({transform}) => {
link.attr("transform", transform);
node.attr("transform", transform);
labels.attr("transform", transform);
}));
}
// progress the simulation
simulation.on("tick", () => {
link
.attr("x1", d => d.source.x)
.attr("y1", d => d.source.y)
.attr("x2", d => d.target.x)
.attr("y2", d => d.target.y)
node
.attr("cx", d => d.x)
.attr("cy", d => d.y)
labels
.attr("x", d => d.x)
.attr("y", d => d.y)
});
}