I'm a civil engineer and I wrote an open source library that compiled a C library to javascript for my own personal projects - epanet-js [1]

A water utility in Spain spun off a start up called Qatium [2] and they used my library as the engine of their simulations and asked me to join.

[1] https://github.com/modelcreate/epanet-js

[2] https://qatium.com/