[curveship]

(x=0)=>()=>++x

[awalGarg]

You can save one character by doing this:

(x=0)=>_=>++x

the underscore is another variable but a single variable does not require parenthesis. So instead of two chars for the two parens, you use a single char for a single letter variable. JS FTW ;)

[posterboy]

that's ascii art, not code

[sladix]

Holy crap, that's what I call refactoring !