> Flow uses nominal typing (similar to functional languages); whereas, TypeScript uses structural typing (similar to Java). Most statically typed languages hav

> Flow uses nominal typing (similar to functional languages); whereas, TypeScript uses structural typing (similar to Java). Most statically typed languages have both nominal and structural types, and, if anything, functional programmers use structural types to a much greater extent than Java programmers: (0) Haskell and ML: Algebraic data types and type classes (Haskell-only) are nominal. Function types, parametric polymorphism, module signatures (ML-only) and object types (OCaml-only) are structural. Type synonyms are of course structural. Type inference makes it practical to work with definitions whose types would be quite large if explicitly annotated, so programmers don't shy away from parameterizing types by four or more type parameters: http://hackage.haskell.org/package/lens-4.14/docs/Control-Lens-Lens.html http://hackage.haskell.org/package/lens-4.14/docs/Control-Le... , http://hackage.haskell.org/package/pipes-4.2.0/docs/Pipes.html http://hackage.haskell.org/package/pipes-4.2.0/docs/Pipes.ht... (1) Java and C#: Classes, interfaces and variances (C#-only) are nominal. Generics and wildcards (Java-only) are structural. No type synonyms and limited inference make working with syntactically large types very inconvenient. And guess which is the most vilified feature of Java's type system among Java programmers themselves...