I went through the steps described on the readme.md and when I ran 'ng serve'

I was getting the following errors:

ERROR in src/app/services/rdf.service.ts(33,12): error TS2503: Cannot find namespace '$rdf'.
src/app/services/rdf.service.ts(41,18): error TS2503: Cannot find namespace '$rdf'.
src/app/services/rdf.service.ts(323,58): error TS2503: Cannot find namespace '$rdf'.

I checked the file src/app/services/rdf.service.ts
and the following line was commented out:
import * as $rdf from 'rdflib'

I uncommented it and the project built and I was able to load the page.

@james-martin-jd - is there a reason why that line needed to commented out?
I saw that you recently commented it out to fix an "issue where rdflib was throwing errors"
1c91ae7#diff-dca975bf5ad72321f0990d8416fddab0