I have created a D3 line chart in my application. Initially, the line chart was working fine until I found a problematic scenario with the data. This Code Sample shows the initial solution where it shows three lines for three countries and when hovering over them we can select them. But I encountered a scenario where all the data points are getting the same and it causes the three lines to overlap with each other. Therefore no more I can see there are three lines there but only a one. So users can't see that three locations are shown in this chart and they can't select one of them. Is there a way to avoid this problem or a solution for this.
This fiddle shows the erroneous situation : https://jsfiddle.net/yasirunilan/rvoft1h8/
var data = [{
name: "USA",
values: [{
date: "2000",
price: "100"
},
{
date: "2001",
price: "110"
},
{
date: "2002",
price: "145"
},
{
date: "2003",
price: "241"
},
{
date: "2004",
price: "101"
},
{
date: "2005",
price: "90"
},
{
date: "2006",
price: "10"
},
{
date: "2007",
price: "35"
},
{
date: "2008",
price: "21"
},
{
date: "2009",
price: "201"
}
]
},
{
name: "Canada",
values: [{
date: "2000",
price: "100"
},
{
date: "2001",
price: "110"
},
{
date: "2002",
price: "145"
},
{
date: "2003",
price: "241"
},
{
date: "2004",
price: "101"
},
{
date: "2005",
price: "90"
},
{
date: "2006",
price: "10"
},
{
date: "2007",
price: "35"
},
{
date: "2008",
price: "21"
},
{
date: "2009",
price: "201"
}
]
},
{
name: "Maxico",
values: [{
date: "2000",
price: "100"
},
{
date: "2001",
price: "110"
},
{
date: "2002",
price: "145"
},
{
date: "2003",
price: "241"
},
{
date: "2004",
price: "101"
},
{
date: "2005",
price: "90"
},
{
date: "2006",
price: "10"
},
{
date: "2007",
price: "35"
},
{
date: "2008",
price: "21"
},
{
date: "2009",
price: "201"
}
]
}
];
var width = 500;
var height = 300;
var margin = 50;
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.timeParse("%Y");
data.forEach(function(d) {
d.values.forEach(function(d) {
d.date = parseDate(d.date);
d.price = +d.price;
});
});
/* Scale */
var xScale = d3.scaleTime()
.domain(d3.extent(data[0].values, d => d.date))
.range([0, width - margin]);
var yScale = d3.scaleLinear()
.domain([0, d3.max(data[0].values, d => d.price)])
.range([height - margin, 0]);
var color = d3.scaleOrdinal(d3.schemeCategory10);
/* Add SVG */
var svg = d3.select("#chart").append("svg")
.attr("width", (width + margin) + "px")
.attr("height", (height + margin) + "px")
.append('g')
.attr("transform", `translate(${margin}, ${margin})`);
/* Add line into SVG */
var line = d3.line()
.x(d => xScale(d.date))
.y(d => yScale(d.price));
let lines = svg.append('g')
.attr('class', 'lines');
lines.selectAll('.line-group')
.data(data).enter()
.append('g')
.attr('class', 'line-group')
.on("mouseover", function(d, i) {
svg.append("text")
.attr("class", "title-text")
.style("fill", color(i))
.text(d.name)
.attr("text-anchor", "middle")
.attr("x", (width - margin) / 2)
.attr("y", 5);
})
.on("mouseout", function(d) {
svg.select(".title-text").remove();
})
.append('path')
.attr('class', 'line')
.attr('d', d => line(d.values))
.style('stroke', (d, i) => color(i))
.style('opacity', lineOpacity)
.on("mouseover", function(d) {
d3.selectAll('.line')
.style('opacity', otherLinesOpacityHover);
d3.selectAll('.circle')
.style('opacity', circleOpacityOnLineHover);
d3.select(this)
.style('opacity', lineOpacityHover)
.style("stroke-width", lineStrokeHover)
.style("cursor", "pointer");
})
.on("mouseout", function(d) {
d3.selectAll(".line")
.style('opacity', lineOpacity);
d3.selectAll('.circle')
.style('opacity', circleOpacity);
d3.select(this)
.style("stroke-width", lineStroke)
.style("cursor", "none");
});
/* Add circles in the line */
lines.selectAll("circle-group")
.data(data).enter()
.append("g")
.style("fill", (d, i) => color(i))
.selectAll("circle")
.data(d => d.values).enter()
.append("g")
.attr("class", "circle")
.on("mouseover", function(d) {
d3.select(this)
.style("cursor", "pointer")
.append("text")
.attr("class", "text")
.text(`${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);
});
/* Add Axis into SVG */
var xAxis = d3.axisBottom(xScale).ticks(5);
var yAxis = d3.axisLeft(yScale).ticks(5);
svg.append("g")
.attr("class", "x axis")
.attr("transform", `translate(0, ${height-margin})`)
.call(xAxis);
svg.append("g")
.attr("class", "y axis")
.call(yAxis)
.append('text')
.attr("y", 15)
.attr("transform", "rotate(-90)")
.attr("fill", "#000")
.text("Total values");
