Add CoffeeScript friendly kv args to Underscore.js

underscoreR.coffee

#names of functions to create KV versions of and arg lists (in order) 
to_kv = throttle: ['func', 'wait'], delay: ['func', 'wait'], defer: ['func'], bind: ['func', 'context']

mixin = {}
for name, arglist of to_kv
  do (name, arglist) ->
    mixin["#{name}KV"] = (kvargs) ->
      args = (kvargs[arg] for arg in arglist when kvargs[arg]?)
      if arglist.length isnt args.length then throw new Error "missing args"
      _[name](args...)

_.mixin mixin