High Charts export-server not rending legend LabelFormatter - node.js

Question

I have the following code for the node.js high-Charts export-server the legend is showing but the label formatted is not applied and the function is not executed also
I have tried the load function also and it is not working, I tried custom HTML and it is now showing also
let chartDetails = {
type: "png",
options: {
chart: {
type: "pie",
showInLegend: true,
dataLabels: {
enabled: false
}
},
title: {
align: 'left',
floating: false,
text: 'Main Title',
style: {
fontSize: '24px'
}
},
subtitle: {
verticalAlign: 'middle',
align: 'center',
floating: false,
text: '<b>300</b><br>Total Issues',
style: {
fontSize: '30px'
}
},
plotOptions: {
pie: {
innerSize: '70%',
shadow: false,
showInLegend: true,
dataLabels: {
enabled: false,
}
}
},
legend: {
enabled: true,
floating: true,
borderWidth: 0,
align: 'right',
layout: 'vertical',
verticalAlign: 'middle',
useHTML: true,
labelFormatter: function () {
console.log("this: is equal to ");
console.log(this);
return 'custom word';
}
}
,
series: [
{
data: [
{
name: "a",
y: 100
},
{
name: "b",
y: 20
},
{
name: "c",
y: 50
}
]
}
]
}
};
I expected 'custom word' instead 'a','b','c' is showing

Answer 1

It seems when using node-export-server as a module callback functions are not supported. Check this thread on the module github: https://github.com/highcharts/node-export-server/issues/122.
As a workaround, you can use labelFormat property instead of labelFormatter:
legend: {
enabled: true,
floating: true,
borderWidth: 0,
align: 'right',
layout: 'vertical',
verticalAlign: 'middle',
useHTML: true,
labelFormat: "custom word"
}