How to color individual boxes of an echarts boxplot based on function - echarts

Question

How do I color each boxes individually in an echarts box-plot based on a function?
The following function works on a simple bar chart and colors the bars appropriately:
series: [{
data: [120, 200, 150, 80, 70, 110, 130],
type: 'bar',
showBackground: true,
itemStyle: {
color: function(seriesIndex) {
return ProfessionColor[seriesIndex.name.split("_", 1).toString()]
},
},
}]
However, it does not work on a box-plot:
series: [{
name: 'boxplot',
type: 'boxplot',
datasetIndex: 1,
itemStyle: {
color: function(seriesIndex) {
return ProfessionColor[seriesIndex.name.split('_', 1)];
}
},
encode: {
tooltip: [1, 2, 3, 4, 5]
}
},
{
name: 'outlier',
type: 'scatter',
encode: {
x: 1,
y: 0
},
datasetIndex: 2
}
]
If I provide color: "red" rather than a function all boxes are colored red. This leads me to believe that it needs to happen in the transform.config which I can't find in the documents or tutorial.
Echarts Box-Plot currently
The link is the complete charts in its current form.

Answer 1

Apparently, echarts only allows scripting (i.e., using a function for) either the line color -- option itemStyle.borderColor or the fill color -- option itemStyle.color.
The difference between the two appears to be made by the value of the internal property BoxplotSeriesModel#visualDrawType. It is now set to "stroke", which means that borderColor can be set via a function.
Since you wanted to set the fill color, its value should be set to "fill". I searched a way to change that property - it was rather difficult for echarts don't document an API for extensions. Still, navigating the source code I came up with this hacky solution:
const BoxplotSeriesModel = echarts.ComponentModel.getClassesByMainType('series').find(cls=>cls.type==='series.boxplot');
const BoxplotSeriesModelFill = function(...args){
const _this = new BoxplotSeriesModel(...args);
_this.visualDrawType = 'fill';
return _this;
}
BoxplotSeriesModelFill.type = BoxplotSeriesModel.type;
echarts.ComponentModel.registerClass(BoxplotSeriesModelFill);
That's a "patch" to be applied at the beginning of your script, immediately after you have the echarts global defined.
Here's a forked version of your code that uses that patch. The only other change I made was to set a borderColor (can now only be a fixed value) to black.

Answer 2

This will not get you all the way, but if you add colorBy: "data" to your options and remove the itemStyle, it will look like this: