[yatsyk]

Shameful plug: I've made an npm library for treemaps [1]. There is a sample app [2] that can draw a treemap of your drive file system, similar to SequoiaView or Disk Inventory X, in the browser using the file system API.

[1] https://treemap.yatsyk.com/ [2] https://treemap.yatsyk.com/folderstat