Shape generation function used by Treemap example

Hi there,

I was looking to reproduce the treemap example shown in the plotly.js documentation, but was unable to find where the Treemap.generate funciton used to generate the shapes is coming from.

Is this part of plotly or D3, or another third party library?

Thanks

Here it is https://cdn.rawgit.com/imranghory/treemap-squared/master/min/treemap-squared-0.5.min.js

Perfect, thank you very much!