This repository is not actively developed any more.
If you need support or customization for existing projects, it is still available (please contact info at ifcquery.com)
For new projects, xeoIFC (https://github.com/xeofoundry/xeoIfc) is recommended.
It is much more recent, the geometry quality and robustness is much better, CSG operations are more stable, and it can run also in WASM.
XeoIFC has a very high performance and geometry quality. With all my test files (several thousand), xeoIFC has better quality and performance than any other IFC tool, web based or desktop.