d3.nest retains node properties after rollup

[DDDgfx]

Its difficult to understand why rollup should strip leaf node properties, when there are all kinds of reasons those properties might be desired for viz/labelling. etc once the nest is fed to d3.hierarchy. I understand that I can have rollup deliver back an object rather than a single value but 1) that is laborous and idiosyncratic to the data set and 2) d3.hierarchy then finds 0/undefined in the "value" property for non leaf nodes.
Maybe stratify handles this better, but in my environment its not feasible to ask my non-viz counterparts to keep a bunch of dead/non-functional rows in their data so stratify can find them.

Can there be a way to for rollup to retain leaf properties in the nest?

[DDDgfx]

reference of my stratify comment: d3/d3-hierarchy#33

[DDDgfx]

Furthur investigation indicates that that adding .sum() to my heirarchy also strips node properties. Why not a properties node? Consider how labels are created in the example linked above.

node.append("div")
      .attr("class", "node-label")
      .text(function(d) { return d.parent.parent.data.key + " to " + d.parent.data.key + "\n" + d.data.key; });

So in order to use something within a leaf, you'd either need to make sure its a key along the way, or do lookup from the OG data. Property portability might be more flexible.

[DDDgfx]

Curious to know if this suggestion is reasonable.

[mbostock]

Apologies for the delayed reply. This doesn’t seem to be an issue with d3.nest. nest.rollup doesn’t strip properties; if you specify a rollup function, you can do whatever you like with the passed-in array of values, and the returned value is what becomes the resulting entry.value.

Perhaps you meant to suggest a change to d3.hierarchy instead? That also doesn’t strip properties, but it does (intentionally) wrap the input data. You can access the original input as node.data.