Error ReferenceError: CanvasGradient is not defined - node.js

Question

I am trying to create a line chart using chartjs-node package. Below is the code. When I give the data of dataset as a small set like data: [20, 15, 60, 60, 65, 30, 70], it works fine. But if I change it to a list that I want to populate as in dataFirst dataset below, I get the error "ReferenceError: CanvasGradient is not defined". I donot understand the reason. Please help. Thanks.
public createChart(cData) {
const chartNode = new chart(1000, 800);
const dataFirst = {
label: 'Heat Sink',
data: cData,
lineTension: 0.3,
fill: false,
borderColor: 'red',
backgroundColor: 'transparent',
pointBorderColor: 'red',
pointBackgroundColor: 'lightgreen',
pointRadius: 5,
pointHoverRadius: 15,
pointHitRadius: 30,
pointBorderWidth: 2,
pointStyle: 'rect',
};
const dataSecond = {
label: 'TVK Channel 9',
data: [20, 15, 60, 60, 65, 30, 70],
lineTension: 0.3,
fill: false,
borderColor: 'purple',
backgroundColor: 'transparent',
pointBorderColor: 'purple',
pointBackgroundColor: 'lightgreen',
pointRadius: 5,
pointHitRadius: 30,
pointBorderWidth: 2,
};
const chartOptions = {
legend: {
display: true,
position: 'top',
labels: {
boxWidth: 80,
fontColor: 'black',
},
},
};
const speedData = {
labels: ['0s', '10s', '20s', '30s', '40s', '50s', '60s'],
datasets: [dataFirst, dataSecond],
};
const chartJsOptions = {
type: 'line',
data: speedData,
options: chartOptions,
};

Answer 1

I found the solution. The number of labels should match the number of data points.

Answer 2

In canvas for node implementation you need to export CanvasGradient class yourself. According to this issue: https://github.com/Automattic/node-canvas/issues/990
You can do this:
["CanvasRenderingContext2D", "CanvasPattern", "CanvasGradient"].forEach(obj => {
console.log(obj, canvas[obj])
global[obj] = canvas[obj]
})