Question

It doesn’t really have to add newlines, just something readable.

Anything better than this?

str = "line 1" +
      "line 2" +
      "line 3";

Answer 1

Almost identical to NickFitz’s answer:

var str = [""
    ,"line 1"
    ,"line 2"
    ,"line 3"
].join("");
// str will contain "line1line2line3"

The difference, the code is slightly more maintainable because the lines can be re-ordered without regard to where the commas are. No syntax errors.