I am trying to generate a line chart where the X axis values are a string. In the example that D3 has the X axis is a date. How can I change the format of the X axis based on the example that D3 shows.
D3 example of a Line Chart
https://observablehq.com/@d3/line-chart
LineChart = // Copyright 2021 Observable, Inc.
// Released under the ISC license.
// https://observablehq.com/@d3/line-chart
function LineChart(data, {
x = ([x]) => x, // given d in data, returns the (temporal) x-value
y = ([, y]) => y, // given d in data, returns the (quantitative) y-value
defined, // for gaps in data
curve = d3.curveLinear, // method of interpolation between points
marginTop = 20, // top margin, in pixels
marginRight = 30, // right margin, in pixels
marginBottom = 30, // bottom margin, in pixels
marginLeft = 40, // left margin, in pixels
width = 640, // outer width, in pixels
height = 400, // outer height, in pixels
xType = d3.scaleUtc, // the x-scale type
xDomain, // [xmin, xmax]
xRange = [marginLeft, width - marginRight], // [left, right]
yType = d3.scaleLinear, // the y-scale type
yDomain, // [ymin, ymax]
yRange = [height - marginBottom, marginTop], // [bottom, top]
yFormat, // a format specifier string for the y-axis
yLabel, // a label for the y-axis
color = "currentColor", // stroke color of line
strokeLinecap = "round", // stroke line cap of the line
strokeLinejoin = "round", // stroke line join of the line
strokeWidth = 1.5, // stroke width of line, in pixels
strokeOpacity = 1, // stroke opacity of line
} = {}) {
// Compute values.
const X = d3.map(data, x);
const Y = d3.map(data, y);
const I = d3.range(X.length);
if (defined === undefined) defined = (d, i) => !isNaN(X[i]) && !isNaN(Y[i]);
const D = d3.map(data, defined);
// Compute default domains.
if (xDomain === undefined) xDomain = d3.extent(X);
if (yDomain === undefined) yDomain = [0, d3.max(Y)];
// Construct scales and axes.
const xScale = xType(xDomain, xRange);
const yScale = yType(yDomain, yRange);
const xAxis = d3.axisBottom(xScale).ticks(width / 80).tickSizeOuter(0);
const yAxis = d3.axisLeft(yScale).ticks(height / 40, yFormat);
// Construct a line generator.
const line = d3.line()
.defined(i => D[i])
.curve(curve)
.x(i => xScale(X[i]))
.y(i => yScale(Y[i]));
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,${height - marginBottom})`)
.call(xAxis);
svg.append("g")
.attr("transform", `translate(${marginLeft},0)`)
.call(yAxis)
.call(g => g.select(".domain").remove())
.call(g => g.selectAll(".tick line").clone()
.attr("x2", width - marginLeft - marginRight)
.attr("stroke-opacity", 0.1))
.call(g => g.append("text")
.attr("x", -marginLeft)
.attr("y", 10)
.attr("fill", "currentColor")
.attr("text-anchor", "start")
.text(yLabel));
svg.append("path")
.attr("fill", "none")
.attr("stroke", color)
.attr("stroke-width", strokeWidth)
.attr("stroke-linecap", strokeLinecap)
.attr("stroke-linejoin", strokeLinejoin)
.attr("stroke-opacity", strokeOpacity)
.attr("d", line(I));
return svg.node();
}
My Configuration of the Line Chart
<script>
let chartTitles = document.getElementById('chart-title').innerHTML = 'Line Chart';
let chartColor = '#d13c4b';
let chartHeight = 500;
let chartWidth;
let yAxisLabel = "↑ Daily close ($)";
let statusValues = [{status: 'PHA', value: phaCat},
{status: 'Local', value: localCat},];
console.log(statusValues);
chart = LineChart(statusValues, {
x: d => d.status,
y: d => d.value,
width: chartWidth,
height: chartHeight,
color: chartColor,
yLabel: yAxisLabel
})
console.log(chart);
document.getElementById("d3_chart").append(chart);
</script>
