Drilldown in Sankey Diagram - highcharts

Question

I'm looking for example code on how to implement a drilldown in a sankey diagram.
I tried using the drilldown code from the column drilldown demo but it didn't work for sankey.
The intended functionality is very similar to a dendogram, i.e- click a node to hide reveal child nodes.
Example:
https://jsfiddle.net/y_tddel/d7jby2z1/5/
.
In this example each node in the second column will be clickable and have their own child nodes.The expanded view of Indo-Iranian node is shown as as an example.

Answer 1

Series.point.events can be used to trigger the event when the user clicks on any node, and update the series data, and adding a back button.
Link: https://api.highcharts.com/highcharts/series.sankey.point.events.click
Look at the following code sample:
Highcharts.chart('container', {
series: [{
point: {
events: {
click: function (e) {
console.log(e, 'e')
let series = this.series,
chart = series.chart;
if (this.isNode) {
if (isDrilldown[isDrilldown.length - 1] != this.name && drilldown_data.hasOwnProperty(this.name)) {
chart.backButton = chart.renderer.button('back', chart.plotLeft, 20, function () {
isDrilldown.pop();
d = JSON.parse(JSON.stringify(drilldown_data[isDrilldown[isDrilldown.length - 1]]));
series.update({data: d});
chart.backButton.destroy();
chart.title.show();
}).add()
isDrilldown.push(this.name);
chart.title.hide()
this.series.update({
data: JSON.parse(JSON.stringify(drilldown_data[this.name]))
})
}
}
}
}
},
keys: ['from', 'to', 'weight', 'drilldown'],
data: JSON.parse(JSON.stringify(plot_data)),
type: 'sankey'
}],
});
Demo: https://jsfiddle.net/deveshgoyal/1zcnuq5b/2/

Answer 2

Current drilldown module is not compatible with the sankey series. You will need to create your own drilldown logic. Below is a basic demo which shows how to update series on click event - which could be treated as an drilldown to other series.
Demo: https://jsfiddle.net/BlackLabel/hn19xga5/
events: {
click() {
let series = this.series,
chart = series.chart;
if (!isDrilldown) {
chart.backButton = chart.renderer.button('back', 20, 20, function() {
series.update({
data: initialData
})
chart.backButton.destroy();
isDrilldown = false;
}).add()
isDrilldown = true;
}
this.series.update({
data: drilldown1
})
}
}
API: https://api.highcharts.com/highcharts/series.sankey.data.events.click
API: https://api.highcharts.com/class-reference/Highcharts.SVGRenderer#button
API: https://api.highcharts.com/class-reference/Highcharts.Series#update