Rails' Array#to_sentence for AngularJS

test.haml

%span
  %p {{ [] | toSentence }}
  %p {{ ['my parents'] | toSentence }}
  %p {{ ['my parents', 'Ayn Rand'] | toSentence }}
  %p {{ ['my parents', 'Ayn Rand', 'God'] | toSentence }}

toSentence.coffee

app.filter 'toSentence', ->
  (items) ->
    l = items.length
    if l == 0
      ''
    else if l == 1
      items[0]
    else if l == 2
      "#{items[0]} and #{items[1]}"
    else
      items.slice(0, -1).join(', ') + ', and ' + items[l - 1]