best_standards_support

rubyonrails-core
1

File ./lib/rails/generators/rails/app/templates/config/environments/development.rb.tt: # Only use best-standards-support built into browsers config.action_dispatch.best_standards_support = :builtin

File ./lib/rails/application.rb: middleware.use ::ActionDispatch::BestStandardsSupport, config.action_dispatch.best_standards_support if config.action_dispatch.best_standards_support

What's the point of setting action_dispatch.best_standards_support to Symbol when we only care whether it is true or false ? Do we expect that in future there will be other possible values for this setting ?

Robert Pankowecki

2

And one more question: Why is this line "config.action_dispatch.best_standards_support = :builtin" added only to environments/development.rb file ? Why are we adding it when the default is True (based on ./actionpack/lib/action_dispatch/railtie.rb) ?

The fact that we are setting it only in development environment to an unsupported value that does not change the behavior at all makes me a little confused.

Robert Pankowecki

3

I don’t know why it’s different in the development environment but from actionpack/lib/action_dispatch/middleware/best_standards_support.rb:

case type

when true

"IE=Edge,chrome=1"

when :builtin

"IE=Edge"

when false

nil

end

The bit of history I found: "[Improve best_standards_support to use only IE=Edge in development mode](https://github.com/rails/rails/commit/6767946374353f90ce05e68d38bcb93dcb8bae56)"

So it's not an unsupported value, but that doesn't say why we do so in the development environment.

Franck
4

My guess is that we do now want to test IE using Chrome mode in development environment because we want to use the application like a user with normal IE to see possible differences in behavior.

Robert Pankowecki

5

...My guess is that we do NOT want ...