TP 2 simple line + mouseover

forked from romsson's block: TP 2 simple line + mouseover

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    .line {
      fill: none;
      stroke: black;
      stroke-width: 1.5px;
    }
  </style>
</head>

var svg = d3.select("body").append("svg")
      .attr("width", 960)
      .attr("height", 500);

var width = 800;
    var height = 400;

// See formats https://bl.ocks.org/zanarmstrong/raw/05c1e95bf7aa16c4768e/
    // Data sample {"name": "G", "value": 10, "date": "2016-07"}
    var parseDate = d3.timeParse("%Y-%m");
    var displayDate = d3.timeFormat("%b %y");
    var displayValue = d3.format(",.0f");
    
    // Ordinal scale
    var x = d3.scaleTime()
        .range([0, width]);

// Linear scale
    var y = d3.scaleLinear()
        .range([height, height - 200]);

var line = d3.line()
        .x(function(d) { return x(d.date); })
        .y(function(d) { return y(d.value); });
    
    var g = svg.append("g")
    	.attr("transform", "translate(50, 0)")
    
   	d3.json("dataset.json", function(error, data) {
	  	if (error) throw error;

// Pre-processing
      data.forEach(function(d) {
				d.value = +d.value;
        d["date"] = parseDate(d["date"]);
      });
      
      x.domain(d3.extent(data, function(d) { return d.date; }));
			y.domain([0, d3.max(data, function(d) { return d.value; })]);
      
      svg.selectAll(".label").data(data).enter()
       .append("text")
      	.attr("class", "label")
        .text(function(d, i) { return displayDate(d.date); })
        .attr("y", 420)
        .attr("x", function(d) { return x(d.date); })
        .style("font-size", 10)
        .style("font-family", "monospace");

// Display last value
      g.selectAll(".value").data([data[data.length -1]]).enter()
       .append("text")
        .text(function(d, i) { return displayValue(d.value); })
        .attr("class", "value")
        .attr("y", function(d) { return y(d.value); })
        .attr("x", width + 10)
        .style("font-size", 20)
        .style("font-family", "monospace");

g.selectAll(".line").data([data]).enter().append("path")
        .attr("class", "line")
        .attr("d", line);
      g.selectAll("dot").data(data).enter()
      	.append("circle")
      	.style("fill","grey").style("opacity", 0.4)
      	.attr("r",10)
      	.attr("cx",function(d){return x(d.date) ;})
    		.attr("cy",function(d){return y(d.value);})
     		.on("mouseover",gestionMouseOver)
      	.on("mouseout",gestionMouseOut)
      ;
				
      function gestionMouseOver (d,i){
      	d3.select(this).style("fill","red").style("opacity", 1);
        svg.append("text")
          	.attr("id",function(){return "val" + i;})
          	.attr("x",function(){return x(d.date)+55;})
        		.attr("y",function(){return y(d.value)-15;})
        .text(function(){return d.value;});
        svg.append("line")
        		.attr("id", function(){return "dash" + i;})
          	.attr("x1",function(){return x(d.date)+50;})
            .attr("y1",function (){return y(d.value);})
        		.attr("x2",function(){return x(d.date)+50;})
            .attr("y2",420)
        		.attr("stroke-width", 1)
        		.style("stroke", "black")
        		.style("stroke-dasharray",("3,3"));
        		
      }
      
			function gestionMouseOut (d,i) {
        d3.select(this).style("fill","grey").style("opacity", 0.4);
        d3.select("#val" + i).remove();
        d3.select("#dash" + i).remove();
      }
    });

</script>
</body>

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