Which is the more semantically correct fun2?

which.coffee

fun1 = ->
  fun2 true, (err, resp) ->
    if !err
      doStuff()
    else
      console.log "Error: #{err}"
      res.end JSON.stringify err
    
fun2 = (val, callback) ->
  if val
    #The line below (see: null)
    callback null, 'okay'
    #The line above
  else
    callback 'error', null
    
fun2 = (val, callback) ->
  if val
    #The line below (see: false)
    callback false, 'okay'
    #The line above
  else
    callback 'error', null