[Chris2048]

> Having worked mostly with C# in the last months, I remembered how cool it is to have a statically typed language

Really? I used to work with Java. I sometimes miss type checking, but I don't miss the Java type system - is C# a lot better?

[pistacchioso]

I find C# to be better, but things are ok everywhere as long as they're kept easy. I think that function (param?: Array) is simply better than function (param) because the IDE can hint you that the function accepts a single parameter, that it is optional and warns you if you try to pass a string because it must be an Array.