Simple graph with filled area in v4

This is a simple graph demonstrating the addition of a filled area in conjunction with a line graph. This was written using d3.js v4 and is a follow on to the simple graph example here.

This graph is part of the code samples for the update to the book D3 Tips and Tricks to version 4 of d3.js.

forked from d3noob's block: Simple graph with filled area in v4

<!DOCTYPE html>
<meta charset="utf-8">
<style> /* set the CSS */

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

.area {
    fill: lightsteelblue;
  }
  
  .sla__line {
    stroke: #F74C7D;
		stroke-width: 2;
    stroke-dasharray: 6 3;
  }
  
  .sla__label {
    fill: white;
  }
  
  .issue__line {
    stroke: steelblue;
		stroke-width: 20;
    opacity: .5;
  }

</style>
<body>

<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
  // set the dimensions and margins of the graph
  const margin = {top: 20, right: 20, bottom: 30, left: 80};
  const width = 960 - margin.left - margin.right;
  const height = 500 - margin.top - margin.bottom;
  const arr = [];

// parse the date / time
  const dateFormat = "%B %d, %Y";
  const parseTime = d3.timeParse(dateFormat);
  const formatTime = d3.timeFormat(dateFormat);
  const randNum = (min, max) => Math.floor(Math.random() * (max - min + 1)) + min;
  
	// Set up random data
	const numDays = 45;
  const graphData = Array(numDays)
  .fill()
  .map((_, index) => {
    const newD = new Date();
		newD.setDate(newD.getDate() - index);
    return {
      date: parseTime(formatTime(newD)),
      value: randNum(5, 15) 
    }
  });
  
  const fillArr = (num) => {
    if (arr.includes(num)) {
      fillArr(randNum(num - 1, 20));
    } else {
      arr.push(num);
      return num;
    }
  };
  
  for (let i=0; i < 11; i++) {
    fillArr(randNum(1, 20));
  }
  
  const lineData = Array(10)
  	.fill()
    .map((_, index) => graphData[arr[index]]);
  
  // set the ranges
  const x = d3.scaleTime().range([0, width]);
  const y = d3.scaleLinear().range([height, 0]);

// define the area
  const area = d3.area()
    .x(d => x(d.date))
    .y0(height)
    .y1(d => y(d.value))
    .curve(d3.curveMonotoneX);

// define the line
  const valueline = d3.line()
    .x(d => x(d.date))
    .y(d => y(d.value))
    .curve(d3.curveMonotoneX);

// append the svg obgect to the body of the page
  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 + ")");
  
 	// scale the range of the data
  x.domain(d3.extent(graphData, d => d.date));
  y.domain([0, d3.max(graphData, d => d.value + 5)]);
  
  // add the X Axis
  svg.append("g")
  		.attr("class", "x-axis")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x));

// add the Y Axis
  svg.append("g")
  		.attr("class", "y-axis")
      .call(d3.axisLeft(y));
  
  // Add grid
  svg.selectAll('.y-axis .tick line')
    .attr('stroke', '#E3E3E3')
    .attr('stroke-width', 1)
    .attr('x1', 0)
    .attr('x2', width);

svg.selectAll('.x-axis .tick line')
    .attr('stroke', '#E3E3E3')
    .attr('stroke-width', 1)
    .attr('y1', 0)
    .attr('y2', -height)

// add the area
  svg.append("path")
    .data([graphData])
    .attr("class", "area")
    .attr("d", area);

// add the valueline path.
  svg.append("path")
      .data([graphData])
      .attr("class", "line")
      .attr("d", valueline);
  
  // Draw HZ line
  addLine(svg);

// Draw Vert lines
  addVertLines(svg);
  
  function addVertLines(svg) {
    const vertLine = svg.selectAll('.issue')
      .data(lineData)
      .enter()
      .append('g')
      .attr('transform', d => `translate(${x(d.date)}, 0)`);

vertLine.append('line')
      .attr('y1', 0)
      .attr('y2', height)
      .attr('class', 'issue__line');
  }
  
  function addVertLine(pos) {
    svg.append("line")
      .attr("x1", x(today))  //<<== change your code here
      .attr("y1", 0)
      .attr("x2", x(today))  //<<== and here
      .attr("y2", height - margin.top - margin.bottom)
      .style("stroke-width", 2)
      .style("stroke", "red")
      .style("fill", "none");
  }
  
  function addLine(svg) {
    const rectHeight = 20;
    const rectYoffset = -10;
    const rectXoffset = 0;
    const rectPadding = 10;

// Add SLA element group and position
    const sla = svg.selectAll('.sla')
    .data([10])
    .enter()
    .append('g')
    .attr('transform', d => `translate(-50, ${y(d)})`);

// Add SLA line
    sla.append('line')
      .attr('x1', 0)
      .attr('x2', width + 50)
      .attr('class', 'sla__line');

// Add SLA label group (default position)
    const labelEl = sla.append('g');

// Position text box
    const rectEl = labelEl.append('rect')
      .attr('rx', '3')      	
      .attr('ry', '3')
      .attr('fill', '#F74C7D')
      .attr('height', rectHeight)
      .attr('transform', `translate(${rectXoffset}, ${-rectHeight - rectYoffset})`);

// Position text
    const textEl = labelEl.append('text')
      .attr('class', 'sla__label')
      .text(d => `${d}ms`)
      .attr('dx', rectPadding / 2)
      .attr('dy', rectPadding / 2);

// Read box width from text length
    rectEl
      .attr('width', textEl.node().getComputedTextLength() + rectPadding);
  }
</script>
</body>

https://d3js.org/d3.v4.min.js