code: function (container, toAdd) {
              var entry;
              for (var i = 0, len = toAdd.length; i < len; i++) {
                  entry = toAdd[i];
                  this.addIfMissing(entry, container);
              }
          }
docs: Add all the entries of the array toAdd into the array container only if container does not already have them
  @param {Array} container
  @param {Array} toAdd