ordinal mulit line curve

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <script src="https://d3js.org/d3-scale.v1.min.js"></script>
  <script src="https://d3js.org/d3-axis.v1.min.js"></script>
  <script src="https://d3js.org/d3-array.v1.min.js"></script>
  <script src="https://d3js.org/d3-interpolate.v1.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
  </style>
</head>

<body>

var margin = {top: 100, right: 100, bottom: 100, left: 100},
        width = 960 - margin.left - margin.right,
        height = 500 - margin.top - margin.bottom;

var fruits = [
      { name: "apple", value: 100 },
      { name: "orange", value: 200 }, 
      { name: "banana", value: 200 }, 
      { name: "grapefruit", value: 400 },
      { name: "papaya", value: 150 }, 
      { name: "coconut", value: 400 }, 
    ];

var data = [];
    for (var i=0; i<10; i++) {
      var fruit = fruits.map( 
        (d,j) => ({ 
            name: d.name, 
            value: d.value + Math.random() * 30 * 
          		(j === 0 ? 0 : 
               	(j === fruits.length - 1 ? 0 : (Math.random() > 0.5 ? 1 : -1)))
          })
      );
      
      data[i] = Array.prototype.slice.call(fruit);
    } 
    
    var x = d3.scalePoint()
    .domain(fruits.map(x => x.name))
    .range([0, width]);

var y = d3.scaleLinear()
    .domain(d3.extent(fruits,(x) => x.value))
    .range([height, 0]);

var color = d3.scaleLinear() 
    	.domain([0, data.length])
    	.interpolate(d3.interpolateRgb)
    	.range(['lightgray', 'black'])
    
    var xAxis = d3.axisBottom().scale(x);

var line = d3.line()
      .x(d => x(d.name))
      .y(d => y(d.value))
     	.curve(d3.curveNatural);

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 + ")");

svg.append("g")
      .attr("class", "x-axis")
      .call(xAxis);
    
    d3.select('.x-axis').attr('transform', 'translate(0,' + height + ')');
		
    var gLine = svg.selectAll('.gline')
    	.data(data)
    	.enter()
    	.append('g').classed('gline', true);
    
    gLine
      .append("path")
      .attr("d", d => line(d))
    	.style('fill', 'none')
      .style('stroke', (d,i) => color(i));

</script>
</body>

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

https://d3js.org/d3-scale.v1.min.js

https://d3js.org/d3-axis.v1.min.js

https://d3js.org/d3-array.v1.min.js

https://d3js.org/d3-interpolate.v1.min.js