Structural typing is extremly helpful/practical, it lowers "type-friction" a lot. I have a dream that flow/ts will be lifted up to js spec one day (yes, I know,

Structural typing is extremly helpful/practical, it lowers "type-friction" a lot. I have a dream that flow/ts will be lifted up to js spec one day (yes, I know, that's why I said "dream"). With this the language would be open to things like multiple dispatch a'la julia/traits/typeclasses and/or pattern matching - which would (imho) place the language at the top for couple of decades. This kind of stuff is unfortunatelly outside of scope of flow/ts as it would require runtime support, which flow/js explicitly don't provide (ie. stripped types makes valid js, all type-stuff happens at "compile" time only, without access to runtime at all). But flow/ts is major step towards practical solution, it covers something like 65% of properly typed language (properly = algebra on types, structural+nominal typing, opaque types, nullability exposed at type level, aggressive inferrence etc.)