How to display stacked line chartjs - chart.js

Question

I try to display stacked line chart but it doesn't work.
Could you advise where I should change with the following code?
window.onload=function(){
var ctx = document.getElementById("myChart").getContext("2d");
var data = {
labels: {{subcategories|tojson}},
datasets: [
{
1st_sample_dataset
},
{
2nd_sample_dataset
}
]
},
options = {
scales: {
yAxes: [{
stacked: true
}]
}
};
new Chart(ctx).Line(data, {
onAnimationComplete: function () {
var sourceCanvas = this.chart.ctx.canvas;
var targetCtx = document.getElementById("myChartAxis").getContext("2d");
targetCtx.canvas.width = copyWidth;
targetCtx.drawImage(sourceCanvas, 0, 0, copyWidth, copyHeight, 0, 0, copyWidth, copyHeight);
}
});
}
And this is actual display.

Answer 1

From your code I presume you're using an old version of chart.js.
new Chart(ctx).Line(data, {
...
Charts are now created in a different way.
var myChart = new Chart(ctx, {
type: 'line',
...
If you switch to version 2.9.3., it works fine as the following code sample illustrates.
new Chart(document.getElementById('myChartAxis'), {
type: 'line',
data: {
labels: ['A', 'B', 'C', 'D'],
datasets: [
{
label: 'WARNINGS',
data: [1, 2, 3, 2],
borderColor: 'rgb(255, 159, 64)',
backgroundColor: 'rgba(255, 159, 64, 0.2)'
},
{
label: 'ERRORS',
data: [1, 2, 1, 3],
borderColor: 'rgb(255, 99, 132)',
backgroundColor: 'rgba(255, 99, 132, 0.2)'
}
]
},
options: {
scales: {
yAxes: [{
stacked: true
}]
}
}
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.3/Chart.bundle.min.js"></script>
<canvas id="myChartAxis" height="90"></canvas>