Easy example that I know of: the Mediasoup project is a library written in C++ for streaming video over the internet. It is published as a Node package and offers a JS API. Upon installing, it would just download the appropriate C++ sources and compile them on the spot. The project maintainers wanted to write code, not manage precompiled builds, so that was the most logical way of installing it. Note that a while ago they ended up adding downloadable builds for the most common platforms, but for anything else the expectation still was (and is, I guess) to build sources at install time.