Rescript compiles to really efficient JS. Learning React with ReasonML (Rescripts predecessor) spoiled me, in a bad way. Waiting for TS to compile was really painfull. In Reason it took fractions of a second.
+1 the ReScript compiler is a beast: not only is it fast at generating JS, the JS it generates is optimised for performance[1]. If you are using React, it's better to go for ReScript rather than using Ramda or lodash-fp.