How do I properly format long compound if statements in Coffeescript

CoffeeScript will not interpret the next line as the body of the statement if the line ends with an operator, so this is ok:

# OK!
if a and
not 
b
  c()

it compiles to

if (a && !b) {
  c();
}

so your if could be formatted as

# OK!
if (foo is 
bar.data.stuff and 
foo isnt bar.data.otherstuff) or 
(not foo and not bar)
  awesome sauce
else lame sauce

or any other line-breaking scheme so long as the lines end in and or or or is or == or not or some such operator

As to indentation, you can indent the non-first lines of your if so long as the body is even more indented:

# OK!
if (foo is 
  bar.data.stuff and 
  foo isnt bar.data.otherstuff) or 
  (not foo and not bar)
    awesome sauce
else lame sauce

What you cannot do is this:

# BAD
if (foo  #doesn't end on operator!
  is bar.data.stuff and 
  foo isnt bar.data.otherstuff) or 
  (not foo and not bar)
    awesome sauce
else lame sauce