how to write setTimeout with params by Coffeescript

Question

I think it's a useful convention for callbacks to come as the last argument to a function. This is usually the case with the Node.js API, for instance. So with that in mind:

delay = (ms, func) -> setTimeout func, ms

delay 1000, -> something param

Granted, this adds the overhead of an extra function call to every setTimeout you make; but in today's JS interpreters, the performance drawback is insignificant unless you're doing it thousands of times per second. (And what are you doing setting thousands of timeouts per second, anyway?)

Of course, a more straightforward approach is to simply name your callback, which tends to produce more readable code anyway (jashkenas is a big fan of this idiom):

callback = -> something param
setTimeout callback, 1000

setTimeout ( ->
  something param
), 1000

The parentheses are optional, but starting the line with a comma seemed messy to me.

setTimeout -> 
  something param
, 1000

This will result in a roughly equivalent translation (thanks @Joel Mueller):

setTimeout (-> something param), 1000

Note that this isn't an exact translation because the anonymous function returns the result of calling something(param) instead of undefined, as in your snippet.

I find this the best method to do the same,

setTimeout (-> alert "hi"), 1000

another option:

setTimeout(
    -> something param
    1000
)