[hantusk]

I think https://github.com/uwdata/mosaic is really promising here. See the example https://idl.uw.edu/mosaic/examples/linear-regression.html where the user can recalculate a linear regression based on their selection.

You'd still need to implement any custom selection widgets, data transformations (like other statistical tests) etc. still missing, but i like the technical design to build on top off. It uses https://github.com/observablehq/plot under the hood, which aims to have just as flexible a grammar as ggplot (already quite capable) but with interactive features (built by the creator of d3 and uses it under its hood).