A solution to the "staircase problem" posed by node.js's reliance on callbacks. See http://blog.yuvalshavit.com/2013/07/tutorials-need-section-on-best-practices.html

callbacks.coffee

# In some util class...
handler = (errText, f) ->
  (err, rows) ->
    if err?
      console.log "#{errText}: #{err}"
    else
      f(rows)

# And then:
m = myqlPool()
barHandler = handler "Couldn't get a bar", (bars) ->
  console.log("Found a bar!", bar) for bar in bars
fizzHandler = handler "Couldn't get fizzes", (fizzes) ->
  foos = [fizz.foo for fizz in fizzes]
  for foo in foos
    do (foo) ->
      m.query selectBar, [foo], barHandler
m.query getFizzes, fizzHandler