Single point on multiple line linear graph with Chart.js - chart.js

Question

I have a multi line linear chart made with Chart.js like this:
var ctx = document.getElementById("myChart").getContext("2d");
const colors = {
green: {
fill: '#e0eadf',
stroke: '#5eb84d',
},
lightBlue: {
stroke: '#6fccdd',
},
darkBlue: {
fill: '#92bed2',
stroke: '#3282bf',
},
purple: {
fill: '#8fa8c8',
stroke: '#75539e',
},
};
const loggedIn = [26, 36, 42, 38, 40, 30, 12];
const available = [34, 44, 33, 24, 25, 28, 25];
const availableForExisting = [16, 13, 25, 33, 40, 33, 45];
const unavailable = [5, 9, 10, 9, 18, 19, 20];
const xData = [13, 14, 15, 16, 17, 18, 19];
const myChart = new Chart(ctx, {
type: 'line',
data: {
labels: xData,
datasets: [{
label: "Unavailable",
fill: true,
backgroundColor: colors.purple.fill,
pointBackgroundColor: colors.purple.stroke,
borderColor: colors.purple.stroke,
pointHighlightStroke: colors.purple.stroke,
borderCapStyle: 'butt',
data: unavailable,
}, {
label: "Available for Existing",
fill: true,
backgroundColor: colors.darkBlue.fill,
pointBackgroundColor: colors.darkBlue.stroke,
borderColor: colors.darkBlue.stroke,
pointHighlightStroke: colors.darkBlue.stroke,
borderCapStyle: 'butt',
data: availableForExisting,
}, {
label: "Available",
fill: true,
backgroundColor: colors.green.fill,
pointBackgroundColor: colors.lightBlue.stroke,
borderColor: colors.lightBlue.stroke,
pointHighlightStroke: colors.lightBlue.stroke,
borderCapStyle: 'butt',
data: available,
}, {
label: "Logged In",
fill: true,
backgroundColor: colors.green.fill,
pointBackgroundColor: colors.green.stroke,
borderColor: colors.green.stroke,
pointHighlightStroke: colors.green.stroke,
data: loggedIn,
}]
},
options: {
responsive: false,
// Can't just just `stacked: true` like the docs say
scales: {
yAxes: [{
stacked: true,
}]
},
animation: {
duration: 750,
},
}
});
<script src="https://cdn.jsdelivr.net/npm/chart.js#2.8.0"></script>
<canvas id="myChart" width="400" height="400"></canvas>
My problem is that when I go over a point all points on that column activate.
I want to activate just the single point on the selected line.
So, just to be clear, this is what I have now: Actual Behaviour
And this is what i want: Expected Behaviour
Anyone could help me on this?

Answer 1

You need to set the hover interaction mode option like so:
options: {
hover: {
mode: 'nearest'
}
}
Working example:
var ctx = document.getElementById("myChart").getContext("2d");
const colors = {
green: {
fill: '#e0eadf',
stroke: '#5eb84d',
},
lightBlue: {
stroke: '#6fccdd',
},
darkBlue: {
fill: '#92bed2',
stroke: '#3282bf',
},
purple: {
fill: '#8fa8c8',
stroke: '#75539e',
},
};
const loggedIn = [26, 36, 42, 38, 40, 30, 12];
const available = [34, 44, 33, 24, 25, 28, 25];
const availableForExisting = [16, 13, 25, 33, 40, 33, 45];
const unavailable = [5, 9, 10, 9, 18, 19, 20];
const xData = [13, 14, 15, 16, 17, 18, 19];
const myChart = new Chart(ctx, {
type: 'line',
data: {
labels: xData,
datasets: [{
label: "Unavailable",
fill: true,
backgroundColor: colors.purple.fill,
pointBackgroundColor: colors.purple.stroke,
borderColor: colors.purple.stroke,
pointHighlightStroke: colors.purple.stroke,
borderCapStyle: 'butt',
data: unavailable,
}, {
label: "Available for Existing",
fill: true,
backgroundColor: colors.darkBlue.fill,
pointBackgroundColor: colors.darkBlue.stroke,
borderColor: colors.darkBlue.stroke,
pointHighlightStroke: colors.darkBlue.stroke,
borderCapStyle: 'butt',
data: availableForExisting,
}, {
label: "Available",
fill: true,
backgroundColor: colors.green.fill,
pointBackgroundColor: colors.lightBlue.stroke,
borderColor: colors.lightBlue.stroke,
pointHighlightStroke: colors.lightBlue.stroke,
borderCapStyle: 'butt',
data: available,
}, {
label: "Logged In",
fill: true,
backgroundColor: colors.green.fill,
pointBackgroundColor: colors.green.stroke,
borderColor: colors.green.stroke,
pointHighlightStroke: colors.green.stroke,
data: loggedIn,
}]
},
options: {
responsive: false,
// Can't just just `stacked: true` like the docs say
scales: {
yAxes: [{
stacked: true,
}]
},
animation: {
duration: 750,
},
hover: {
mode: 'nearest'
},
}
});
<script src="https://cdn.jsdelivr.net/npm/chart.js#2.8.0"></script>
<canvas id="myChart" width="400" height="400"></canvas>