Which company introduced the first mass-produced chocolate bar?

the question needs to be changed, it's only true for the USA

compared to European chocolate, American chocolate is terrible.

It’s the first time I have heard that Hershey make “chocolate”. I believe the first chocolate bars were made by Cadbury in the U.K. They have been bought by Mondelez so are no longer making chocolate.

Putterill, What's the rest of the world 's answer ?