Maximilian uses a mixture of Cheerp and Emscripten to transpile the C++ code into something that can be run in the browser. Call overhead in Emscripten can be slow, and this is magnified by single sample processing, so some small functions are transpiled directly to javascript using Cheerp, thereby bypassing call overhead. These functions are transpiled using the make script in the purejs folder, generating a file build/maximilian.transpile.js which is then included in the other builds. You can then build for either audio worklet or script processor node systems.
The functions that are compiled with Cheerp are specified in purejs/module-bindings.js, the rest are set up in src/maximilian.embind.cpp. Warning: Cheerp doesn't do overrides but also doesn't warn for this so watch out for unexplained errors due to this issue.
Install the Emscripten SDK and Cheerp
cd [root]/js/purejs
make
cd [root]/js/script-processor-node
make
The library can be found in the build subfolder
cd [root]/js/audio-worklet
make
The library can be found in the build subfolder