can I replace multiline like this in vim?

Question

I want keep my js in this style. I want write a map in vim to do it faster.

from:

var a = x;
var b = y;
var c = z;

to:

var a = x
  , b = y
  , c = z
  ;

Answer 1

Use the following command.

%s/;\nvar /\r , /gc