6.1 line chart | multiple

<!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.v4.min.js"></script>

<p id="h1">LINE CHART | MULTI</p>
<div id="link"> by
<a href="https://slides.com/sandravizmad">SANDRA</a> | <a href="https://data.oecd.org/air/air-pollution-exposure.htm">DATA </a></div>

<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 axis stylings*/

.x-axis text {
  font-family:'Montserrat Alternates', sans-serif;
  font-weight:400;
  font-size:10px;
  opacity:0.5;
  fill:white;
}

.y-axis text {
  font-family:'Montserrat Alternates', sans-serif;
  font-weight:400;
  font-size:9px;
  opacity:0.5;
  fill:white;
}

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

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

.y-axis line, .x-axis line {
  fill:none;
  stroke-width:0.5;
  stroke-opacity:0.5;
  stroke:white;
  stroke-dasharray:2;
}

/*Defining chart stylings*/

.line {
  fill:none;
  stroke:#85f6fa;
  stroke-width:1px;
}

</style>
</head>

//Margin conventions
var m = {top:100, right:50, bottom:50, left:40}
    w = 800 - m.left - m.right,
    h = 800 - 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})`);

//Define the format
var parseDate = d3.timeParse("%Y");
var formatDate = d3.timeFormat("%Y");

//Data loading
d3.csv(
  "https://gist.githubusercontent.com/sandravizz/e324c94814d802e6c268e01266204045/raw/4ed6f4c9554bda1c77004037fbc2a670104a4031/OECD%2520Air%2520pollution%2520by%2520country%2520group%2520and%2520year",
  data => {

//Nesting the data by symbol
  var country = d3.nest()
  		.key(d => d.LOCATION)
      .entries(data);

//Total list of names
  allKeys = country.map(d => d.key)

//Check
  console.log(allKeys);

//Parse and caculate some values for each symbols
  country.forEach(s => {s.values.forEach(d => {d.Value = +d.Value;
                                               d.TIME = parseDate(d.TIME);
                                               });
                         s.maxValue = d3.max(s.values, d => d.Value);
                         s.sumValue = d3.sum(s.values, d => d.Value);
                        });

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

//Y scale
  var y = d3.scaleLinear()
      .domain([0, d3.max(country.map(d => d.maxValue))])
      .range([h, 40]);

//Line generator
  var line = d3.line()
      .defined(function(d) {return d !== null;})
      .x(d => x(d.TIME))
      .y(d => y(d.Value));

//X axis
  svg.append("g")
     .attr("class", "x-axis")
  	 .attr("transform", `translate(15, ${h})`)
     .call(d3.axisBottom()
             .scale(x)
      		   .ticks(10)
             .tickPadding(10)
             .tickSize(0));

//Y axis
  svg.append("g")
     .attr("class", "y-axis")
     .attr("transform",`translate(0, ${0})`)
     .call(d3.axisLeft()
             .scale(y)
      		   .tickValues([1, 2, 3, 4, 6, 8, 12, 20, 30, 40])
             .tickSize(-w)
  					 .tickPadding(10));

//Draw the lines
  svg.selectAll(".line")
     .data(country)
     .enter()
     .append("path")
     .attr("class", "line")
     .attr("d", d => line(d.values))

});

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

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