Are they planning to implement pattern matching in ts? It seems like such a good fit for language type system
At this point TS is trying to keep runtime syntax in line with TC-39 (the language committee in charge of JS) proposals that reach Stage 3 (and thus likely to reach Stage 4 and general acceptance/use in the browser).
There is currently a Stage 1 proposal for a pattern matching syntax presented to TC-39. If it reaches Stage 3 then it is presumed likely Typescript will implement it.