Multiple Zoomable Areas SVG

forked from interwebjill's block: Zoomable Area SVG

Changes from the version above are noted in code comments.

<!DOCTYPE html>
<style>
  /* to prevent browser overscrolling */
  html {
    overflow: hidden;
  }
  /* different way of setting clipping path */
  .area {
    clip-path: url(#clip);
  }
  .PEMS  {
      fill: rgba(249, 208, 87, 0.8);
    }

.TBLkW  {
      fill: rgba(54, 174, 175, 0.5);
    }
</style>
<svg width="960" height="500"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
    margin = {top: 20, right: 20, bottom: 30, left: 60},
    width = +svg.attr("width") - margin.left - margin.right,
    height = +svg.attr("height") - margin.top - margin.bottom,
    g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var parseDate = d3.timeParse("%Y/%m/%d %H:%M"),
    formatDate = d3.timeFormat("%Y");

var x = d3.scaleTime()
    .range([0, width]);

var y = d3.scaleLinear()
    .range([height, 0]);

var xAxis = d3.axisBottom(x);

var yAxis = d3.axisLeft(y);

var area = d3.area()
    .curve(d3.curveStepAfter)
// added x domain, changed data value
    .x(function(d) { return x(d.date); })
    .y0(y(0))
    .y1(function(d) { return y(d.kW); });

// var areaPath = g.append("path")
//     .attr("clip-path", "url(#clip)")
//     .attr("fill", "steelblue");

// group to hold the multiple paths  
var dataPaths = g.append("g")
    .attr("class", "dataPaths");

var yGroup = g.append("g");

var xGroup = g.append("g")
    .attr("transform", "translate(0," + height + ")");

var zoom = d3.zoom()
    .scaleExtent([1, Infinity])
    .translateExtent([[0, 0], [width, height]])
    .extent([[0, 0], [width, height]])
    .on("zoom", zoomed);

var zoomRect = svg.append("rect")
    .attr("width", width)
    .attr("height", height)
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
		.attr("class", "zoom-area")
    .attr("fill", "none")
    .attr("pointer-events", "all")
    .call(zoom);

// g.append("clipPath")
//     .attr("id", "clip")
//   .append("rect")
//     .attr("width", width)
//     .attr("height", height);
  
// did the clip path a little differently
var defs = svg.append("defs");

defs.append("clipPath")
    .attr("id", "clip")
    .append("rect")
    .attr("width", width)
    .attr("height", height);

// changed data source
d3.csv("kW_sample.csv", type, function(error, data) {
  if (error) throw error;

// each column of data becomes a source
  var sources = data.columns.slice(1).map(function(id) {
    return {
      id: id,
      values: data.map(function(d) {
        return {date: d.date, kW: d[id]};
      })
    };
  });
   
  var xExtent = d3.extent(data, function(d) { return d.date; });
  x.domain(xExtent);
	// changed to account for multiple columns of data
  y.domain([
    0,
    d3.max(sources, function(c) { return d3.max(c.values, function(v) { return v.kW; }); })
  ]);
  yGroup.call(yAxis);
//   areaPath.datum(data);
// look in elements inspector in devtools to see how these groups are organized
  var sourcedataPaths = dataPaths.selectAll("g")
  .data(sources)
  .enter()
  .append("g")
  .attr("class", "sourcedataPaths");

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