code: function uniq(arr) {
    var theSet = new pouchdbCollections.Set(arr);
    var result = new Array(theSet.size);
    var index = -1;
    theSet.forEach(function (value) {
      result[++index] = value;
    });
    return result;
  }
docs: uniq an array of strings, order not guaranteed similar to underscore/lodash _.uniq