More readable coffeescript conditionals

gistfile1.coffee

# This is part of a simple javascript router I'm writing.
# When a link is clicked, the router checks to see if the url should trigger a route callback
# Here I demonstrate a way to improve long conditional statements with coffeescript and underscore.js

# Before: Concise but hard to read, hard to comment and hard to modify.

routeUrl: (url)->
  return false if url is window.location.pathname || url.match /^http|^#/ || url.match /\.(png|gif|je?pg|pdf)$/i
  url

# After: I create an array of conditionals, then using _.contains I check if any of the conditions pass
# This improves legibility and it's easier to add comments and modifications.

routeUrl: (url)->
  
  # Do not route url if
  ignore = [
    # url is the current url
    url is window.location.pathname
      
    # url is a remote or in-page url
    url.match /^http|^#/
    
    # urls points to image assets
    url.match /\.(png|gif|je?pg|pdf)$/i
  ]
  
  # Return the url or false if it shouldn't be routed
  if _.contains(ignore, true) then false else url