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I have implemented a D3v3 Multi-line chart in my application. As I'm quite new to D3 charts I looked for some online resources and came up with this. Initially, I had to display Years on X-axis and it was working properly. This fiddle shows it (https://jsfiddle.net/yasirunilan/tz57wc29/13/). Then according to a new requirement I need to show the data distribution with months in X-Axis, The difference is the X-axis doesn't always start with the month of January. As given in the Dataset it might start from October of a year to October of a year to September of Next Year. In that case, I faced a problem in displaying the line and X-Axis values in the chart. Can someone provide direction for this problem?

Fiddle: https://jsfiddle.net/yasirunilan/v160sr4z/10/

    var data = [{

    name: "USA",

    values: [{

        date: "October",

        price: "100"

      },

      {

        date: "November",

        price: "110"

      },

      {

        date: "December",

        price: "145"

      },

      {

        date: "January",

        price: "241"

      },

      {

        date: "February",

        price: "101"

      },

      {

        date: "March",

        price: "90"

      },

      {

        date: "April",

        price: "120"

      },

      {

        date: "May",

        price: "135"

      },

      {

        date: "June",

        price: "99"

      },

      {

        date: "July",

        price: "105"

      },

      {

        date: "August",

        price: "101"

      },

      {

        date: "September",

        price: "106"

      }

    ]

  },

  {

    name: "UK",

    values: [{

        date: "October",

        price: "130"

      },

      {

        date: "November",

        price: "120"

      },

      {

        date: "December",

        price: "115"

      },

      {

        date: "January",

        price: "220"

      },

      {

        date: "February",

        price: "100"

      },

      {

        date: "March",

        price: "140"

      },

      {

        date: "April",

        price: "90"

      },

      {

        date: "May",

        price: "235"

      },

      {

        date: "June",

        price: "160"

      },

      {

        date: "July",

        price: "86"

      },

      {

        date: "August",

        price: "201"

      },

      {

        date: "September",

        price: "140"

      }

    ]

  }

];



const margin = 80;

const width = 1000 - 2 * margin;

const height = 550 - 2 * margin;



var duration = 250;



var lineOpacity = "0.25";

var lineOpacityHover = "0.85";

var otherLinesOpacityHover = "0.1";

var lineStroke = "1.5px";

var lineStrokeHover = "2.5px";



var circleOpacity = '0.85';

var circleOpacityOnLineHover = "0.25"

var circleRadius = 3;

var circleRadiusHover = 6;





/* Format Data */

var parseDate = d3.time.format("%B");

data.forEach(function(d) {

  d.values.forEach(function(d) {

    d.date = parseDate.parse(d.date);

    d.price = +d.price;

  });

});



/* Scale */

var xScale = d3.time.scale()

  .domain(d3.extent(data[0].values, d => d.date))

  .range([0, width - margin]);

var yScale = d3.scale.linear()

  .domain([0, d3.max(data[0].values, d => d.price)])

  .range([height - margin, 0]);



// var color = d3.scale.ordinal(d3.schemeCategory10);

var color = d3.scale.category10();



/* Add SVG */

var svg = d3.select("svg")

  .attr("width", (width + margin) + "px")

  .attr("height", (height + margin) + "px")

  .append('g')

  .attr("transform", `translate(${margin}, ${margin})`);





/* Add line into SVG */

var line = d3.svg.line()

  .x(d => xScale(d.date))

  .y(d => yScale(d.price));



let lines = svg.append('g')

  .attr('class', 'lines');



lines.selectAll('.line-group')

  .data(data).enter()

  .append('g')

  .attr('class', 'line-group')

  .on("mouseover", function(d, i) {

    svg.append("text")

      .attr("class", "title-text")

      .style("fill", color(i))

      .text(d.name)

      .attr("text-anchor", "middle")

      .attr("x", (width - margin) / 2)

      .attr("y", 5);

  })

  .on("mouseout", function(d) {

    svg.select(".title-text").remove();

  })

  .append('path')

  .attr('class', 'line')

  .attr('d', d => line(d.values))

  .style('stroke', (d, i) => color(i))

  .style('opacity', lineOpacity)

  .on("mouseover", function(d) {

    d3.selectAll('.line')

      .style('opacity', otherLinesOpacityHover);

    d3.selectAll('.circle')

      .style('opacity', circleOpacityOnLineHover);

    d3.select(this)

      .style('opacity', lineOpacityHover)

      .style("stroke-width", lineStrokeHover)

      .style("cursor", "pointer");

  })

  .on("mouseout", function(d) {

    d3.selectAll(".line")

      .style('opacity', lineOpacity);

    d3.selectAll('.circle')

      .style('opacity', circleOpacity);

    d3.select(this)

      .style("stroke-width", lineStroke)

      .style("cursor", "none");

  });





/* Add circles in the line */

lines.selectAll("circle-group")

  .data(data).enter()

  .append("g")

  .style("fill", (d, i) => color(i))

  .selectAll("circle")

  .data(d => d.values).enter()

  .append("g")

  .attr("class", "circle")

  .on("mouseover", function(d) {

    d3.select(this)

      .style("cursor", "pointer")

      .append("text")

      .attr("class", "text")

      .text(`${d.price}`)

      .attr("x", d => xScale(d.date) + 5)

      .attr("y", d => yScale(d.price) - 10);

  })

  .on("mouseout", function(d) {

    d3.select(this)

      .style("cursor", "none")

      .transition()

      .duration(duration)

      .selectAll(".text").remove();

  })

  .append("circle")

  .attr("cx", d => xScale(d.date))

  .attr("cy", d => yScale(d.price))

  .attr("r", circleRadius)

  .style('opacity', circleOpacity)

  .on("mouseover", function(d) {

    d3.select(this)

      .transition()

      .duration(duration)

      .attr("r", circleRadiusHover);

  })

  .on("mouseout", function(d) {

    d3.select(this)

      .transition()

      .duration(duration)

      .attr("r", circleRadius);

  });







var xAxis = d3.svg.axis().scale(xScale)

  .orient("bottom").tickFormat(d3.time.format("%B")).tickSize(1);



var yAxis = d3.svg.axis().scale(yScale)

  .orient("left").tickSize(1);



svg.append("g")

  .attr("class", "x axis")

  .attr("transform", `translate(0, ${height-margin})`)

  .call(xAxis.ticks(d3.time.year));



svg.append("g")

  .attr("class", "y axis")

  .call(yAxis)

  .append('text')

  .attr("y", 15)

  .attr("transform", "rotate(-90)")

  .attr("fill", "#000")

  .attr('text-anchor', 'middle')

  .text("No. of Employees");

One possible solution is to add years to date field like this

{

    date: "2010-October",

    price: "100"

}

If you are not going to display the year, it may be arbitrary, just make sure, that after December it increases by 1.

Then replace var parseDate = d3.time.format("%B"); with var parseDate = d3.time.format("%Y-%B");

Also replace .call(xAxis.ticks(d3.time.year)); with .call(xAxis.ticks(d3.time.months));

Here is the fiddle: https://jsfiddle.net/p68z0bqo/

Edit: If you can't add years manually, you can try to do this automatically like this:

var parseDate = d3.time.format("%Y-%B");

data.forEach(function(d) {

  var year = 2000;

  d.values.forEach(function(d) {

    if (d.date === 'January') year++;

    d.date = parseDate.parse(year.toString() + '-' + d.date);

    d.price = +d.price;

  });

});

This code only works if all months are present (there are no gaps) and if January is represented exactly as "January" (i.e. it has the same case).