Short snippet that returns an array of unique classes in the DOM

getUniqueClasses

/* returns an array of unique classes in the DOM */
var getUniqueClasses = function() {

  var elementArray = [].slice.call(document.querySelectorAll('*'));

  return _(elementArray)
    .pluck('classList')
    .map(_.toArray)
    .flatten()
    .unique()
    .value()

}