const now = new Date();
const results = entireSatelliteDatabase
  .map(satRec => propagate(satRec, now));

If you tried running this, you know the results: slowdowns which are not suitable for realtime applications.

This is where we went for a mission to make the fastest theoretically possible SGP4/SDP4 implementation available in JavaScript. Meet WebAssembly and a lot of optimization techniques under the hood.