Some projects use Babel for everything, including ts->js transpilation. If you go that route (vs using tsc), it may make it more straightfwd to leverage watch,

Some projects use Babel for everything, including ts->js transpilation. If you go that route (vs using tsc), it may make it more straightfwd to leverage watch, along w/ the rest of the robust babel and webpack tooling that's available. /$0.02