function mapCountry(countryData) {
  var newData = {};

  countryData.forEach((d, i) => {
    newData[d.name] = {
      name: d.name,
      region: d.region,
      income: d.income,
      population: d.population,
      lifeExpectancy: d.lifeExpectancy
    }
  });
  return newData;
}

function getAxes(xScale, yScale) {
  return {
    x: d3.axisBottom().scale(xScale),
    y: d3.axisLeft().scale(yScale)
  }
}

function updateChart(svg, data, country, feature) {
  const countryData = data[country];
  console.log(countryData);
  const metrics = countryData[feature];
  const findMax = (max, cur) => Math.max(max, cur);
  const findMin = (min, cur) => Math.min(min, cur);
  
  const minVal = metrics.map(d => d[1]).reduce(findMin);
  const maxVal = metrics.map(d => d[1]).reduce(findMax);
  const minYear = metrics.map(d => d[0]).reduce(findMin);
  const maxYear = metrics.map(d => d[0]).reduce(findMax);

  
  let yearScale = d3.scaleLinear()
                    .domain([minYear, maxYear])
                    .range([0, +svg.attr('width')]);
  let yScale = d3.scaleLinear()
                 .domain([0, maxVal])
                 .range([svg.attr('height'), 0]);
  var areaObject = d3.area().x(d => yearScale(d[0]))
           .y0(d => yScale(0))
           .y1(d => yScale(d[1]))
           .curve(d3.curveBasis);
  const axes = getAxes(yearScale, yScale);
  svg.select('#x-axis')
     .call(axes.x);
  svg.select('#y-axis')
     .call(axes.y);
  return areaObject(metrics);
  
  // areaChart.data(data)
  //          .x(d => d[0])
  //          .y
}