Comparasion of sprintf() implementations

You may have been wondering what sprint() gives compared to other sprintf() Node.js implementations (perhaps in future I will compare browser-side implementations, but those are harder to find...). This page will compare those. Note that it is in favor of sprintf() as it was written by author, but hopefully it's not biased. sprint() was inspired mainly by Perl implementation of sprintf(), so it contains many features of Perl version of sprintf().

Following function was used to help testing features:

test = ->
  console.log "sprint:  " + try require("sprint") arguments...
  console.log "s:       " + try require("s") arguments...
  console.log "sprintf: " + try require("sprintf").sprintf arguments...
  console.log "printf:  " + try require("printf") arguments...
  console.log "format:  " + try require("format").format arguments...

Feature	sprint	s	sprintf	format	printf
Types
%%	YES	Buggy	YES	YES	YES
%c	YES	No	YES	YES	YES
%s	YES	YES	YES	YES	YES
%d	YES	Buggy	YES	YES	YES
%u	YES	No	Kinda (Math.abs)	YES	No
%o	YES	No	YES	YES	YES (but prefix always appears)
%x	YES	No	YES	YES	YES (but prefix always appears)
%e	YES	No	YES	YES	No
%f	YES	No	YES	YES	YES
%g	YES	No	No	YES	No
%x	YES	No	YES	YES	YES (oddly, prefix never appears unlike %x and %o)
%p	No	No	No	No	No
%n	No	No	No	No	No
%i (alias for %d)	YES	No	No	YES	No
Format parameter index
%1$	YES	No	YES	YES	No
%(option_key)	No	No	YES	YES	No
Flags
Space	YES	No	No	YES	No
+	YES	No	YES	YES	No
-	YES	No	YES	YES	No
#	YES	No	No	YES	No
Vector flag
v	YES	No	No	No	No
Width
Digit	YES	No	YES	YES	No
* (next argument)	YES	No	No	YES	No
Precision
Digit	YES	No	YES	YES	No
* (next argument)	YES	No	No	YES	No
Size argument
Size argument	YES	No	No	Ignored	No

At the end, I wanted to note one of more interesting results in test. While it looks that printf is better than sprint, it's also somewhat more buggy. As for simple examples...

> test('<%*.*f>', 4, 1, 3.14)
sprint:  < 3.1>
s:       <%*.*f>
sprintf: undefined
printf:  <4.000>
format:  <*.*f>