simple_nations_linegraph

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

var margin = {top: 20, right: 50, bottom: 40, left: 50},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;
    
    
var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
		.append("g")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")");
    
var  g = svg.append("g").attr("transform", "translate(" + margin.left + "," + margin.top + ")");

var parseTime = d3.timeParse("%y");
    
var line = d3.line()
	.x(function(d){return x(d[0])})
	.y(function(d){return y(d[1])})
// 	.curve()

function filterJSON(json, location, value){
	    var result = [];
  json.forEach( function(val, idx, arr){
    if(val.name == location){
      result.push(val[value])}
  })
	return result[0];
}

var x = d3.scaleLinear()
    	.range([margin.left,width])
var y = d3.scaleTime()
    	.range([height,margin.bottom])

d3.json("nations.json", function(error,json){
  if (error) throw error;
  
  
  
//   this builds one line for angola income
  data = filterJSON(json, "Angola", "income")
  //sets data domain for x and y
  x.domain(d3.extent(data, function(d){return d[0]}))
  y.domain(d3.extent(data, function(d){return d[1]}))
  //appends x axis
  g.append("g")
  	.attr("class", "axis axis--x")
  	.attr("transform", "translate(0," + height + ")")
  	.call(d3.axisBottom(x))
  // appends y axis
  g.append("g")
  	.attr("class", "axis axis--y")
  	.call(d3.axisLeft(y))
  .append("text")
      .attr("fill", "#000")
      .attr("transform", "rotate(-90)")
      .attr("y", 6)
      .attr("dy", "0.71em")
      .attr("text-anchor", "end")
      .text("income ($)");  
  // appends line
	g.append("path")
  	.datum(data)
    .attr("fill", "none")
    .attr("stroke", "steelblue")
    .attr("stroke-linejoin", "round")
    .attr("stroke-linecap", "round")
    .attr("stroke-width", 1.5)
  	.attr("d", line);
// end angola income 
    
});

</script>
</body>

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