I think Python's is deliberately unexpressive, forcing you to use local variable...

swannodette · on Dec 22, 2011

"everything you do is global, unless you know better"

That is not the JavaScript model at all.

lnanek · on Dec 22, 2011

He is talking about if you don't do anything extra (in this case, use the var keyword). Much like the nonlocal keyword in Python requires knowing about it and wanting to use it in order to actually use it and get the non-default behavior.

swannodette · on Dec 22, 2011

var is not extra in JavaScript the way nonlocal is in Python. var is a language construct that any good JavaScript program must use.

Lazare · on Dec 22, 2011

The point of the linked article is that this is not the CoffeeScript way at all (although the author wishes it was).

rayiner · on Dec 22, 2011

'let' is a way to make things more local! When I say: let x = 0, I'm saying "hey, I don't care what 'x' is in other scopes, in this local scope it's 10, dammit!"

draegtun · on Dec 24, 2011

Yes explicit is best and in Perl its very clear what you want...

  my $x = 10;

whateverer · on Dec 22, 2011

No, the Javascript model is "you name things with `var`, you mutate things with `=`".

Python went for a more complicated scheme of having every variable in a function be a new binding when first assigned, and then it's just mutation (i.e. 'local'), unless explicitly declared to be nonlocal, but it still makes sense with their... penchant for mutable state.

And Coffescript instead went over to PHP to have some of the glue it was eating.

Someone · on Dec 22, 2011

No, the Javascript model is "you name things with `var`, you mutate things with `=`".

If only it were that simple. It also has "you create thing with `var` and sometimes with `=`", plus it does not have block scope:

    if( true)
    {
       var x = 1;
    }
    // x == 1 here.

ryanflorence · on Dec 22, 2011

Functions define scope. The end. Not hard. One rule.