This looks cool, I especially like the "intuitive" longest line algorithm.

~6 years ago I was trying to build a dashboard that displayed real-time measurements from a beehive. The sensors would take temperature, weight, humidity, etc. Back then I used simplify.js [0] which uses two simplification algorithms in two passes. The more compute intensive one is the Ramer Douglas Peucker algorithm [1]. One issue I had with streaming data is that new data points could change the past line, at least with my naive implementation. I'd love to see a real-time / streaming time series simplification algorithm where the past points don't appear to change wildly despite continuing to downsample.

[0] https://github.com/mourner/simplify-js

[1] https://en.wikipedia.org/wiki/Ramer%E2%80%93Douglas%E2%80%93...