[Touche]

   var a = 1;
   a = 2;

   window.someGlobal = 'foo';

[ksikka]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe...

[Touche]

    const a = {b: "foo"};
    a.b = "bar";

[pyrophane]

Yea, const provides immutability with respect to assignment, but without immutable objects and collections, it isn't going to get you all the way.

[dangoor]

    const a = icepick.freeze({b: "foo"});

Granted, that's not as elegant as built-in support but that is literally what I'm doing at the moment when I want immutability.

[Touche]

So if you go to extraordinary lengths you can use JavaScript functionally but it's not very functional by default aside from the first-class functions. Personally I just embrace it's imperative/functional blended nature and go with it.

[omtanks]

Microsoft ruined C# by adding var. var is not your friend. Dynamic typing is not your friend and static languages pretending to be dynamic is akin to evil.

[dllthomas]

Implicit typing is not dynamic typing, or even "pretending to be dynamic". It's also, I think, off topic - as the example seemed to be talking about mutability in JS, with no C# for miles.

[jsprogrammer]

A functional language can allow mutations (see Haskell, LISP, etc.).

All a functional language really needs is first class functions. JS has had that since the very beginning.