7.12 animated line plot | stroke dashoffset button

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

<link href="https://fonts.googleapis.com/css2?family=Montserrat+Alternates:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&family=Montserrat:ital,wght@0,100;0,200;0,300;0,400;0,500;0,600;0,700;0,800;0,900;1,100;1,200;1,300;1,400;1,500;1,600;1,700;1,800;1,900&family=Roboto:ital,wght@0,100;0,300;1,100;1,300&display=swap" rel="stylesheet">

<script src="https://d3js.org/d3.v3.min.js"></script>

<p id="h1">LINE CHART | ANIMATION</p>
<div id="link">by
<a href="https://slides.com/sandravizmad">SANDRA</a></div>

<button id="start" style="position: absolute; margin-left:20px; margin-top:50px;">START</button>
<button id="reset" style="position: absolute; margin-left:90px; margin-top:50px;">RESET</button>

<style>

/*Defining text stylings*/

#h1 {
  font-size:30px;
  margin:30px 0px 0px 20px;
  color:#f5fa91;
  font-family:'Montserrat Alternates', sans-serif;
  font-weight:300;
}

#link {
	font-family:'Montserrat Alternates', sans-serif;
  font-weight:200;
  font-size:10px;
	margin:5px 0px 0px 22px;
  color:white;
}

a:link, a:visited, a:active {
	text-decoration: none;
  color:white;
  border-bottom:1.5px dotted white;
}

body {
  background-color:#011227;
}

/*Defining button stylings*/

#start, #reset {
  font-family:'Montserrat Alternates', sans-serif;
  font-size:12px;
  color:#f5fa91;
  border:0;
  text-align:center;
  background-color:#011227;
}

#start:hover, #reset:hover {
  color:white;
  background-color:#011227;
  border:0;
}

/*Defining chart stylings*/

.line {
   fill:none;
   stroke:#8ff798;
   stroke-width:1.2px;
}

/*Defining axis stylings*/

.y-axis text, .x-axis text {
  font-family:'Montserrat Alternates', sans-serif;
  font-weight:100;
  font-size:9px;
  opacity:1;
  fill:white;
}

.x-axis path, .y-axis path {
  fill:none;
  stroke-width:0;
  stroke-opacity:1;
  stroke:white;
}

.y-axis line, .x-axis line {
  fill:none;
  stroke-width:0;
  stroke-opacity:1;
  stroke:white;
  stroke-dasharray:2;
}

</style>
</head>

//Margin conventions
var m = {top:100, right:50, bottom:50, left:50}
    w = 600 - m.left - m.right,
    h = 600 - m.top - m.bottom;

//Container
var svg = d3.select("body")
    .append("svg")
    .attr("width", w + m.left + m.right)
    .attr("height", h + m.top + m.bottom)
    .append("g")
    .attr("transform", `translate(${m.left}, ${m.top})`);

// Time format
var parseDate = d3.time.format("%b %Y").parse;

//Data loading
d3.csv(
  "https://gist.githubusercontent.com/sandravizz/1c69da3cb900e6c7a515b686b7d7066a/raw/f375606064e5637064c7ef79e4e255f1648c98ce/Unemployment%25202015", 
  data => {

//Data format
data.forEach(d => {
    d.date = parseDate(d.date);
    d.rate = +d.rate;
  });

//X scale
var x = d3.time.scale()
    .domain(d3.extent(data, d => d.date))
    .range([0, w]);

//Y scale
var y = d3.scale.linear()
    .domain(d3.extent(data, d => d.rate))
    .range([h, 0]);

//Line generator
var line = d3.svg.line()
    .x(d => x(d.date))
    .y(d => y(d.rate));

//X axis
svg.append("g")
   .attr("class", "x-axis")
   .attr("transform", `translate(0, ${h})`)
   .call(d3.svg.axis()
		       .scale(x)
           .orient("bottom")
		       .ticks(5)
           .tickSize(0)
           .tickPadding(10));

//Y axis
svg.append("g")
   .attr("class", "y-axis")
   .call(d3.svg.axis()
		       .scale(y)
           .orient("left")
		       .ticks(",.0s")
           .ticks(5)
           .tickSize(-w)
           .tickPadding(10));

//Start button
d3.select("#start")
  .on("click",() => {

//Drawing the line
var path = svg.append("path")
    .datum(data)
    .attr("class", "line")
    .attr("d", line);

//Defining a help variable
var totalLength = path.node().getTotalLength();
    console.log(totalLength);

//Animating the line drawing
path
  .attr("stroke-dasharray", totalLength + " " + totalLength)
  .attr("stroke-dashoffset", totalLength)
  .transition()
  .duration(6000)
  .ease("linear")
  .attr("stroke-dashoffset", 0);
});

//Interactivity for the reset button
d3.select("#reset")
    .on("click",() => d3.select(".line")
        							  .remove());
});

</script>
</body>
</html>

https://d3js.org/d3.v3.min.js