code: function extend(obj /*, obj2, obj3, ... */) {
      var extensions = Array.prototype.slice.call(arguments, 1);
      extensions.forEach(function(extension) {
          var properties = Object.keys(extension);
          properties.forEach(function(property) {
              obj[property] = extension[property];
          });
      });
      return obj;
  }
docs: **extend** shallowly extends a base object with the properties of one or more other objects. Inspired by underscore.