ChartJS: datalabels: show percentage value in Pie piece
Solution 1:
Updated fiddle with 2 decimal precision.
You were not computing the sum, instead storing the current value in sum only for every value.
Here is the working fiddle : https://jsfiddle.net/a1Lvn4eb/55/
var data = [{
data: [50, 55, 60, 33],
labels: ["India", "China", "US", "Canada"],
backgroundColor: [
"#4b77a9",
"#5f255f",
"#d21243",
"#B27200"
],
borderColor: "#fff"
}];
var options = {
tooltips: {
enabled: false
},
plugins: {
datalabels: {
formatter: (value, ctx) => {
let sum = 0;
let dataArr = ctx.chart.data.datasets[0].data;
dataArr.map(data => {
sum += data;
});
let percentage = (value*100 / sum).toFixed(2)+"%";
return percentage;
},
color: '#fff',
}
}
};
var ctx = document.getElementById("pie-chart").getContext('2d');
var myChart = new Chart(ctx, {
type: 'pie',
data: {
datasets: data
},
options: options
});
Solution 2:
I like to add a little in accepted answer,
ctx.chart.data.datasets[0].data
always gives you entire data even if you filter out some data by clicking on legend, means you will always get same percentage for a country even if you filter out some countries.
I have used context.dataset._meta[0].total
to get the filtered total.
Here is the working snippet:
var data = [{
data: [50, 55, 60, 33],
backgroundColor: [
"#4b77a9",
"#5f255f",
"#d21243",
"#B27200"
],
borderColor: "#fff"
}];
var options = {
tooltips: {
enabled: true
},
plugins: {
datalabels: {
formatter: (value, ctx) => {
let sum = ctx.dataset._meta[0].total;
let percentage = (value * 100 / sum).toFixed(2) + "%";
return percentage;
},
color: '#fff',
}
}
};
var ctx = document.getElementById("pie-chart").getContext('2d');
var myChart = new Chart(ctx, {
type: 'pie',
data: {
labels: ['India', 'China', 'US', 'Canada'],
datasets: data
},
options: options
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.7.2/Chart.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]"></script>
<canvas id="pie-chart"></canvas>