Hemant Vishwakarma: How to add gap and text between path in d3.js?

Tuesday 9 May 2023

How to add gap and text between path in d3.js?

I have created a line chart using d3.js, now I want to add the gap and text between the path.

What I have so far.

HTML

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>D3 Stacked Bar and Line Chart</title>
    <script src="https://d3js.org/d3.v5.min.js"></script>
  </head>
  <style>
    .dot {
  display: none;
}

.line-segment {
  fill: none;
  stroke: steelblue;
  stroke-width: 2;
}

.line-text {
  font-size: 12px;
  font-weight: bold;
}
  </style>
  <body>
    <div id="main-chart">
        <svg width="960" height="500"></svg>
    </div>
  </body>
</html>

const data = [
  { year: "2015", value: 120 },
  { year: "2016", value: 200 },
  { year: "2017", value: 300 },
  { year: "2018", value: 400 },
  { year: "2019", value: 500 }
];

const margin = { top: 20, right: 20, bottom: 30, left: 50 };
const width = 600 - margin.left - margin.right;
const height = 400 - margin.top - margin.bottom;

const svg = d3.select("body").append("svg")
  .attr("width", width + margin.left + margin.right)
  .attr("height", height + margin.top + margin.bottom)
  .append("g")
  .attr("transform", `translate(${margin.left},${margin.top})`);

const xScale = d3.scaleBand()
  .range([0, width])
  .domain(data.map(d => d.year))
  .padding(0.2);

const yScale = d3.scaleLinear()
  .range([height, 0])
  .domain([0, d3.max(data, d => d.value)]);

const line = d3.line()
  .x(d => xScale(d.year) + xScale.bandwidth() / 2)
  .y(d => yScale(d.value))
  .defined(function(d) {return !isNaN(d)});

svg.append("g")
  .attr("transform", `translate(0, ${height})`)
  .call(d3.axisBottom(xScale));

svg.append("g")
  .call(d3.axisLeft(yScale));

  svg.selectAll(".line-segment")
  .data(data.slice(0, -1))
  .enter().append("path")
  .attr("class", "line-segment")
  .attr("d", d => {
    const x1 = xScale(d.year) + xScale.bandwidth() / 2;
    const x2 = xScale(data[data.indexOf(d) + 1].year) + xScale.bandwidth() / 2;
    const y1 = yScale(d.value);
    const y2 = yScale(data[data.indexOf(d) + 1].value);
    return `M${x1},${y1} L${x2},${y2}`;
  })
  .attr("stroke", "steelblue")
  .attr("stroke-width", 2);


svg.selectAll(".line-text")
  .data(data)
  .enter().append("text")
  .attr("class", "line-text")
  .text(d => d.value)
  .attr("x", d => xScale(d.year) + xScale.bandwidth() / 2)
  .attr("y", d => yScale(d.value) - 0)
  .attr("text-anchor", "middle")
  .attr("font-size", "12px");

The above solution gives me the following