spectral

https://github.com/rvanwijnen/spectral.js

Spectral.js is a powerful and versatile JavaScript library designed to deliver realistic color mixing in your web-based projects. By harnessing the power of the Kubelka-Munk theory, a robust scientific model that simulates light interaction with paint for true-to-life color mixing, Spectral.js ensures that your projects exhibit vibrant and authentic colors.

References mixbox as its inspiration - mixbox is a similar library for C++ and python