Interaction D3

Built with blockbuilder.org

<!DOCTYPE html>
<meta charset="utf-8">
<style>

.axis--x path {
  display: none;
}

.line {
  fill: none;
  stroke: steelblue;
  stroke-width: 1.5px;
}

</style>
<svg width="960" height="500"></svg>
<script src="//d3js.org/d3.v4.min.js"></script>
<script>

var svg = d3.select("svg"),
    margin = {top: 20, right: 80, bottom: 30, left: 50},
    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 parseTime = d3.timeParse("%Y%m%d");

var x = d3.scaleTime().range([0, width]),
    y = d3.scaleLinear().range([height, 0]),
    z = d3.scaleOrdinal(d3.schemeCategory10);

var line = d3.line()
    .curve(d3.curveBasis)
    .x(function(d) { return x(d.date); })
    .y(function(d) { return y(d.temperature); });

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

var zoom = d3.zoom()
  .scaleExtent([1 / 4, 8])
  .translateExtent([[-width, -Infinity], [2 * width, Infinity]])
  .on("zoom", zoomfunc);
  
var zoomRect = svg.append("rect")
 .attr("width", width)
 .attr("height", height)
 .attr("fill", "none")
 .attr("pointer-events", "all")
 .call(zoom);

d3.tsv("data.tsv", type, function(error, data) {
  if (error) throw error;

var cities = data.columns.slice(1).map(function(id) {
    return {
      id: id,
      values: data.map(function(d) {
        return {date: d.date, temperature: d[id]};
      })
    };
  });

x.domain(d3.extent(data, function(d) { return d.date; }));

y.domain([
    d3.min(cities, function(c) { return d3.min(c.values, function(d) { return d.temperature; }); }),
    d3.max(cities, function(c) { return d3.max(c.values, function(d) { return d.temperature; }); })
  ]);

z.domain(cities.map(function(c) { return c.id; }));

g.append("g")
      .attr("class", "axis axis--x")
      .attr("transform", "translate(0," + height + ")")
      .call(d3.axisBottom(x))
  		.append("text")
      	.attr("x", 400)
      	.attr("dy", "3em")
      	.attr("fill", "#000")
		  .text("Year/Month");

g.append("g")
      .attr("class", "axis axis--y")
      .call(d3.axisLeft(y))
    .append("text")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("fill", "#000")
      .text("Temperature, ºF");

var city = g.selectAll(".city")
    .data(cities)
    .enter().append("g")
  	.attr("id", function(d){return getCityId(d.id)})//attribute to get city id
      .attr("class", "city");

drawCityPath(city);
  
//   city.append("path")
//       .attr("class", "line")
//       .attr("d", function(d) { return line(d.values); })
//       .style("stroke", function(d) { return z(d.id); });

city.append("text")
      .datum(function(d) { return {id: d.id, value: d.values[d.values.length - 1]}; })
      .attr("transform", function(d) { return "translate(" + x(d.value.date) + "," + y(d.value.temperature) + ")"; })
      .attr("x", 3)
      .attr("dy", "0.35em")
      .style("font", "10px sans-serif")
		  .style("cursor", "pointer")
      .text(function(d) { return d.id; })
  		.on("click", function(d){
    var onClick = d3.select(this).classed("onClick");
   
    if(!onClick){          g.select("#"+this.parentNode.id).select("path").remove();
        }
        else {
          drawCityPath(g.select("#"+ this.parentNode.id));
        }
   
    d3.select(this).classed("onClick", !onClick);
  })
  .on("mouseover", function(d){
    var onClick = d3.select(this).classed("onClick");
    if(!onClick){
      g.select("#"+ this.parentNode.id).raise();
      
      g.selectAll(".city").filter(function(c){
        return d.id != c.id;
      })
      .select("path")
      .style("stroke", "lightgray");
    }
  })
  .on("mouseout", function(d){
    g.selectAll(".city")
    .select("path")
    .style("stroke", function(city){
           return z(city.id);
         })
  })
  
  var xExtent = d3.extent(data, function(d) {return d.date; });
  zoom.translateExtent([[x(xExtent[0]), -Infinity], [x(xExtent[1]), Infinity]]);
  zoomRect.call(zoom.transform, d3.zoomIdentity);
  
});
  
function zoomfunc() {
  var zx = d3.event.transform.rescaleX(x);
  g.select(".axis--x")
    .call(d3.axisBottom(x).scale(zx)); 
  line.x(function(d) { return zx(d.date); });
  g.selectAll(".city").select("path").attr("d", function(d){return line(d.values);});
}
  
function drawCityPath(elem) {
  lines = elem.append("path")
      .attr("class", "line")
      .attr("d", function(d) {return line(d.values); })
		  .attr("clip-path", "url(#clip)")
      .style("fill", "none")
      .style("stroke", function(d) { return z(d.id); });
}

function getCityId(state){
  return state.replace(/[^a-zA-Z]/g, "_");
}
  
function type(d, _, columns) {
  d.date = parseTime(d.date);
  for (var i = 1, n = columns.length, c; i < n; ++i) d[c = columns[i]] = +d[c];
  return d;
}

</script>

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