JavaScript version of ActiveSupport's to_sentence method.

gistfile1.js

function toSentence(array) {
  var wordsConnector = ", ",
      twoWordsConnector = " and ",
      lastWordConnector = ", and ",
      sentence;

  switch(array.length) {
    case 0:
      sentence = "";
      break;
    case 1:
      sentence = array[0];
      break;
    case 2:
      sentence = array[0] + twoWordsConnector + array[1];
      break;
    default:
      sentence = array.slice(0, -1).join(wordsConnector) + lastWordConnector + array[array.length - 1];
      break;
  }

  return sentence;
}