Data Blogging.
Published
Edited
Jul 17, 2021
3 forks
Importers
3 stars
chart = {
const svg = d3.select(DOM.svg(width, height))
.style("-webkit-tap-highlight-color", "transparent")
.style("overflow", "visible");
svg.append("g")
.call(xAxis);
svg.append("g")
.call(yAxis);
svg.append("path")
.datum(data)
.attr("fill", "none")
.attr("stroke", color)
.attr("stroke-width", 1.5)
.attr("stroke-linejoin", "round")
.attr("stroke-linecap", "round")
.attr("d", line);
svg
.append("path")
.datum(data)
.style("fill", `url(#mygrad-${color})`)
.style("stroke", "none")
.attr("d", area);
const tooltip = svg.append("g");
svg.on("touchmove mousemove", function(event) {
const {date, value} = bisect(d3.pointer(event, this)[0]);
tooltip
.attr("transform", `translate(${x(date)},${y(value)})`)
.call(callout, `${formatValue(value)}\n${formatDate(date)}`);
});
svg.on("touchend mouseleave", () => tooltip.call(callout, null));
const lg = svg
.append("defs")
.append("linearGradient") // linear gradient
.attr("id", `mygrad-${color}`)
.attr("x1", "0%")
.attr("x2", "0%")
.attr("y1", "0%")
.attr("y2", "100%");
lg.append("stop")
.attr("offset", "0%")
.style("stop-color", color)
.style("stop-opacity", 0.75);
lg.append("stop")
.attr("offset", "100%")
.style("stop-color", color)
.style("stop-opacity", 0.01);
return svg.node();
}
callout = (g, value) => {
if (!value) return g.style("display", "none");
g
.style("display", null)
.style("pointer-events", "none")
.style("font", "10px sans-serif");
const path = g.selectAll("path")
.data([null])
.join("path")
.attr("fill", "white")
.attr("stroke", "black");
const text = g.selectAll("text")
.data([null])
.join("text")
.call(text => text
.selectAll("tspan")
.data((value + "").split(/\n/))
.join("tspan")
.attr("x", 0)
.attr("y", (d, i) => `${i * 1.1}em`)
.style("font-weight", (_, i) => i ? null : "bold")
.text(d => d));
const {x, y, width: w, height: h} = text.node().getBBox();
text.attr("transform", `translate(${-w / 2},${15 - y})`);
path.attr("d", `M${-w / 2 - 10},5H-5l5,-5l5,5H${w / 2 + 10}v${h + 20}h-${w + 20}z`);
}
data = d3.csvParse(await FileAttachment("aapl.csv").text(), d3.autoType).map(({date, close}) => ({date, value: close}))
x = d3.scaleUtc()
.domain(d3.extent(data, d => d.date))
.range([margin.left, width - margin.right])
y = d3.scaleLinear()
.domain([0, d3.max(data, d => d.value)]).nice()
.range([height - margin.bottom, margin.top])
xAxis = g => g
.attr("transform", `translate(0,${height - margin.bottom})`)
.call(d3.axisBottom(x).ticks(width / 80).tickSizeOuter(0))
yAxis = svg => svg
.attr("transform", `translate(${margin.left},0)`)
.call(d3.axisRight(y)
.ticks(height/60)
.tickSize(width - margin.left - margin.right))
.call(g => g.select(".domain")
.remove())
.call(g => g.selectAll(".tick:not(:first-of-type) line")
.attr("stroke-opacity", 0.25)
.attr("stroke-dasharray", "2,2"))
.call(g => g.selectAll(".tick text")
.attr("x", 4)
.attr("dy", -4))
line = d3.line()
.curve(d3.curveLinear)
.defined(d => !isNaN(d.value))
.x(d => x(d.date))
.y(d => y(d.value))
area = d3.area()
.curve(d3.curveLinear)
.defined(function(d) {
return d.date >= 0;
})
.x(function(d) {
return x(d.date);
})
.y0(height - margin.bottom)
.y1(function(d) {
return y(d.value);
});
function formatValue(value) {
return value.toLocaleString();
}
function formatDate(date) {
return date.toLocaleString("en", {
month: "short",
day: "numeric",
year: "numeric",
timeZone: "UTC"
});
}
function formatTick(d) {
const s = (d / 1e6).toFixed(1);
return this.parentNode.nextSibling ? `\xa0${s}` : `$${s} million`;
}
bisect = {
const bisect = d3.bisector(d => d.date).left;
return mx => {
const date = x.invert(mx);
const index = bisect(data, date, 1);
const a = data[index - 1];
const b = data[index];
return b && (date - a.date > b.date - date) ? b : a;
};
}
height = 500
margin = ({top: 20, right: 0, bottom: 20, left: 0})
color = "steelblue"
d3 = require("d3@6")
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.
