Were `do...while` loops left out of CoffeeScript...?

In CoffeeScript, the while loop comes standard:

while x()
   y()

However, the following¹ doesn't work:

do
  y()
while x()

And this is simply sugar for the first example:

y() while x()

Does CoffeeScript come with a built-in loop that executes at least once?

¹As an aside, do is a keyword — it's used to call anonymous functions.

Solution 1:

The CoffeeScript documentation says:

The only low-level loop that CoffeeScript provides is the while loop.

I don't know of a built-in loop that executes at least once, so I guess the alternative is

loop
  y()
  break if x()

I know that this answer is very old, but since I entered here via Google, I thought someone else might as well.

To construct a do...while loop equivalent in CoffeeScript I think that this syntax emulates it the best and easiest and is very readable:

while true
   # actions here
   break unless # conditions here

Your guess is correct: There is no do-while equivalent in CoffeeScript. So you'd typically write

y()
y() while x()

If you find yourself doing this often, you might define a helper function:

doWhile = (func, condition) ->
  func()
  func() while condition()