TS 3.4 has known performance regressions. 3.5 helps, but it's still slower than 3.3. I don't really notice it, though, because I've got `tsc --watch` running i

TS 3.4 has known performance regressions. 3.5 helps, but it's still slower than 3.3. I don't really notice it, though, because I've got `tsc --watch` running in a terminal continuously as I edit code. When tsc sees edits, recompilation competes in tens of ms. It's really quick.