Rails 5.1.5 causing "uninitialized constant Mime::JSON" when rendering json

[chabgood]

While using the syntax
respond_with(@foo)
it was causing the error "uninitialized constant Mime::JSON".

I had to use the original syntax of:
respond_to do |format| format.json { render @foo ) end

[rafaelfranca]

Can you provide an example application that reproduce the issue?

[chabgood]

not at this time, sorry.

[carlosantoniodasilva]

Closing as stale. Happy to help if more info is provided, thanks.