Comma-first vars should be encouraged.

[programmin1]

It says "Any project that cites this document as its base style guide will not accept comma first code formatting", yet I have found comma-first is the best way if you don't want multiple var statements

For example:

var a=1,
      b=3
      c=4

will easily make a global variable c, which is likely not intended.

This style:

var a=1
,   b=3
,   c=4

is more obvious when a comma is missing - causing a global variable to be created.

[acconrad]

While I agree that it is clearer and easier to find missing commas, this is not a universally accepted axiom of the JS community. Plus, there are even differences in opinion within the pro-comma group. I'd argue that the odd spacing would be cumbersome and just easier to write:

var a = 1
  , b = 2
  , c = 3;

and I'd include spaces between = as well.

So as much as I like comma-first, I can't say that as a whole Idiomatic should be evangelizing such a polarizing style.

[leonardolessa]

Well, in my case I believe both are bad options, I think multiple var statements is the way to go, Ben Alman post cleared my mind. And like him, I've never heard a clear case that a single var statement is better than multiple despite being "pretty".

[LiamKenneth]

I agree with @leonardolessa, here is a good article about not using single var.

[stegano]

I agree with @leonardolessa @LiamKenneth, because programmers are not minimizer&optimizer