How all pages of https://material.angular.io can be indexed by google?
check it: https://www.google.co.id/webhp?hl=id&sa=X&ved=0ahUKEwiIu4_2mu3UAhWHKo8KHVk-AagQPAgD#hl=id&q=site:material.angular.io
As you see, that site is using Angular4 (view source)