MAC OS INSTALL php intl extension

Go to https://php-osx.liip.ch

Choose your php version (e.g 7.2)

Copy command

Open terminal

curl -s https://php-osx.liip.ch/install.sh | bash -s 7.2

// this will install php under /usr/local

cd /usr/local/php5-7.2.21-20190811-210031/lib/php/extensions/no-debug-non-zts-20170718

sudo cp intl.so /Applications/XAMPP/xamppfiles/lib/php/extensions/no-debug-non-zts-20170718/intl.so

Restart apache web server

Good luck