Java does nominal typing. That's actually a difference between Flow/TypeScript and Java/C#. The laters do nominal types (that is, if I have type Foo, that has a

Java does nominal typing. That's actually a difference between Flow/TypeScript and Java/C#. The laters do nominal types (that is, if I have type Foo, that has a string property, and type bar, that also has a string property, they are NOT consider the same thing in Java/C#) The difference is that TypeScript does structural typing exclusively, while Flow does structural for interfaces, and nominal for classes. So if you don't use classes, there's no difference (on that front), but if you use classes, there is.