Get a YouTube Video ID from a Url

youtube_url.coffee

# Parses a URL of a YouTube video and
# returns the video id.
# 
# - url - the url of the video
# 
youtube_url_parser = (url) ->

	regex = ///^
		.*               # Zero or more of any character
		(                # Group 1, either:
			  (youtu.be/)  # youtu.be/        - Group 2
			| (v/)         # v/               - Group 3
			| (/u/\w/)     # /u/[a-zA-Z0-9_]/ - Group 4
			| (embed/)     # embed/           - Group 5
			| (watch\?)    # watch?           - Group 6
		)
		\??              # optional question mark
		v?=?             # optional v=
		(
			[^#\&\?]*      # Group 7 - The Video ID.
			               # anything but #,&,? zero
			               # or more times.
		)
		.*               # Any character.
	///

	match = url.match regex

	if match && match[7].length is 11
	then return match[7]
	else return null

This is a prime example of tabs and spaces getting together with one goal: making me rage.