I think the original code of client_side_validations had been changed since you made this tutorial.
For one, their is no line of 658 in rails.validations.js. There are a total of only 574 lines.
Secondly,
gem 'client_side_validations',
github: 'DavyJonesLocker/client_side_validations',
branch: 'rails5'
gem 'client_side_validations-simple_form',
github: 'DavyJonesLocker/client_side_validations-simple_form',
branch: 'rails5'
It would get me an error message when I bundle installed.
I am struglling to get this to work. Could you be kind enough to point me to right direction?