If you get this error:

Fatal error: Class 'IntlDateFormatter' not found in magento2/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php on line 107


that means you need to install Intl php extension.

In order to do it you should go to your php.ini file and uncomment this line:

...
;extension=php_intl.dll
...

to

...
extension=php_intl.dll
...

and restart your nginx.

If after that you get an error below:

PHP Warning: PHP Startup: Unable to load dynamic library '/usr/local/Cellar/php55/5.5.30/lib/php/extensions/no-debug-non-zts-.../php_intl.dll'

that means you don’t have the library php-intl.dll and you need to install it.

There are different ways to do it, but in brew you can run command:

 brew install php55-intl 

it would install the library and create required configuration file:

/usr/local/etc/php/5.5/conf.d/ext-intl.ini