chart = DivergingBarChart(states, {
x: metric === "absolute" ? d => d[2019] - d[2010] : d => d[2019] / d[2010] - 1,
y: d => d.State,
yDomain: d3.groupSort(states, ([d]) => d[2019] - d[2010], d => d.State),
xFormat: metric === "absolute" ? "+,d" : "+%",
xLabel: "← decrease · Change in population · increase →",
width,
marginRight: 70,
marginLeft: 70,
colors: d3.schemeRdBu[3]
})
states = FileAttachment("state-population-2010-2019.tsv").tsv({typed: true})
// Copyright 2021 Observable, Inc.
// Released under the ISC license.
// https://observablehq.com/@d3/diverging-bar-chart
function DivergingBarChart(data, {
x = d => d, // given d in data, returns the (quantitative) x-value
y = (d, i) => i, // given d in data, returns the (ordinal) y-value
title, // given d in data, returns the title text
marginTop = 30, // top margin, in pixels
marginRight = 40, // right margin, in pixels
marginBottom = 10, // bottom margin, in pixels
marginLeft = 40, // left margin, in pixels
width = 640, // outer width of chart, in pixels
height, // the outer height of the chart, in pixels
xType = d3.scaleLinear, // type of x-scale
xDomain, // [xmin, xmax]
xRange = [marginLeft, width - marginRight], // [left, right]
xFormat, // a format specifier string for the x-axis
xLabel, // a label for the x-axis
yPadding = 0.1, // amount of y-range to reserve to separate bars
yDomain, // an array of (ordinal) y-values
yRange, // [top, bottom]
colors = d3.schemePiYG[3] // [negative, …, positive] colors
} = {}) {
// Compute values.
const X = d3.map(data, x);
const Y = d3.map(data, y);
// Compute default domains, and unique the y-domain.
if (xDomain === undefined) xDomain = d3.extent(X);
if (yDomain === undefined) yDomain = Y;
yDomain = new d3.InternSet(yDomain);
// Omit any data not present in the y-domain.
// Lookup the x-value for a given y-value.
const I = d3.range(X.length).filter(i => yDomain.has(Y[i]));
const YX = d3.rollup(I, ([i]) => X[i], i => Y[i]);
// Compute the default height.
if (height === undefined) height = Math.ceil((yDomain.size + yPadding) * 25) + marginTop + marginBottom;
if (yRange === undefined) yRange = [marginTop, height - marginBottom];
// Construct scales, axes, and formats.
const xScale = xType(xDomain, xRange);
const yScale = d3.scaleBand(yDomain, yRange).padding(yPadding);
const xAxis = d3.axisTop(xScale).ticks(width / 80, xFormat);
const yAxis = d3.axisLeft(yScale).tickSize(0).tickPadding(6);
const format = xScale.tickFormat(100, xFormat);
// Compute titles.
if (title === undefined) {
title = i => `${Y[i]}\n${format(X[i])}`;
} else if (title !== null) {
const O = d3.map(data, d => d);
const T = title;
title = i => T(O[i], i, data);
}
const svg = d3.create("svg")
.attr("width", width)
.attr("height", height)
.attr("viewBox", [0, 0, width, height])
.attr("style", "max-width: 100%; height: auto; height: intrinsic;");
svg.append("g")
.attr("transform", `translate(0,${marginTop})`)
.call(xAxis)
.call(g => g.select(".domain").remove())
.call(g => g.selectAll(".tick line").clone()
.attr("y2", height - marginTop - marginBottom)
.attr("stroke-opacity", 0.1))
.call(g => g.append("text")
.attr("x", xScale(0))
.attr("y", -22)
.attr("fill", "currentColor")
.attr("text-anchor", "center")
.text(xLabel));
const bar = svg.append("g")
.selectAll("rect")
.data(I)
.join("rect")
.attr("fill", i => colors[X[i] > 0 ? colors.length - 1 : 0])
.attr("x", i => Math.min(xScale(0), xScale(X[i])))
.attr("y", i => yScale(Y[i]))
.attr("width", i => Math.abs(xScale(X[i]) - xScale(0)))
.attr("height", yScale.bandwidth());
if (title) bar.append("title")
.text(title);
svg.append("g")
.attr("text-anchor", "end")
.attr("font-family", "sans-serif")
.attr("font-size", 10)
.selectAll("text")
.data(I)
.join("text")
.attr("text-anchor", i => X[i] < 0 ? "end" : "start")
.attr("x", i => xScale(X[i]) + Math.sign(X[i] - 0) * 4)
.attr("y", i => yScale(Y[i]) + yScale.bandwidth() / 2)
.attr("dy", "0.35em")
.text(i => format(X[i]));
svg.append("g")
.attr("transform", `translate(${xScale(0)},0)`)
.call(yAxis)
.call(g => g.selectAll(".tick text")
.filter(y => YX.get(y) < 0)
.attr("text-anchor", "start")
.attr("x", 6));
return svg.node();
}
import {howto, altplot} from "@d3/example-components"
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