docs: function init() {
  
      // ex. jif(true, div('blah'))
      registerPlugin('jif', function jif(condition, elem) {
          if (utils.isArray(elem)) {
              elem = runtime.naked(elem, null);
          }
  
          return condition ? elem : null;
      });
  
      // ex. jeach({}, function (item) {})
      registerPlugin('jeach', function jeach(items, cb) {
          if (!items || !cb) { return null; }
  
          var ret = [];
          for (var i = 0, len = items.length; i < len; ++i) {
              ret.push(cb(items[i]));
          }
  
          return ret;
      });
  }