Use D3 functionality to create the `children` hierarchy
See this code.
This should be rewritten purely using d3.rollup / d3.nest / d3.group / d3.hierarchy / d3.stratify / something like that.
See this code.
This should be rewritten purely using d3.rollup / d3.nest / d3.group / d3.hierarchy / d3.stratify / something like that.