From @vkichline on October 8, 2015 22:32

I see this pattern in the Web Application template's _ValidationScriptsPartial.cshtml:

<environment names="Development"> … </environment> <environment names="Staging,Production"> … </environment> 

This pattern above seems brittle; if I add a new environment setting, I have a lot of searching and modification to do.

I wish I had something like:

<environment names="Development"> … </environment> <environment names="!Development"> … </environment> 

…or:

<environment names="Development"> … <else> … </environment> 

Copied from original issue: aspnet/Razor#567