The ol/source/Delaunay computes a Delaunay triangulation of a vector source (points).
Experimental this feature is still in progress and may be buggy.
NB: the algorithm is incremental and not very efficient but it computes the triangulation directly in a ol/source/Vector.
You can add/remove vertex from the point source and get the resulting triangles directly in the triangle source.
If you're looking for you'd better see an other algorithme like mapbox/delaunator
This is more to use with interactive processes to maintains a triangulation on state while interacting.