Is React.Component the default extension when exporting?

Question

I am looking through some React projects, and sometimes see-

export default () => {

But other times I see-

export default class

Answer 1

The first one is a functional component. However the other code will export a regular class/React component.

For example

export default (withHistory, onUpdate) => {
    const history = new HashHistory;
  return (
    
      
    
  );
};

Will compile (at least with Babel+webpack) to

...
var _reactRouterLibHashHistory = __webpack_require__(35);
var _reactRouterLibHashHistory2 = _interopRequireDefault(_reactRouterLibHashHistory);
exports['default'] = function (withHistory, onUpdate) {
      var history = new _reactRouterLibHashHistory2['default']();
      return React.createElement(
        _reactRouter.Router,
        { history: history, onUpdate: onUpdate },
        React.createElement(_reactRouter.Route, { path: '/', component: _routesIndex2['default'] })
      );
    };
module.exports = exports['default'];
...