Getting rid of inefficient constantize

Trying to improve performance of one controller I've found the following:

def application_klass

  @application_klass ||= "application/#{params[:type]}".classify.constantize

end

There are Application::Rental and Application::Bridge models in our rails app, so the method above was used in two places:

1. application_klass.to_s – to get the model name as a string

2. application_klass.model_name.human – to get a class name without module prefix

I've refactored method in the following way:

def application_klass

  @application_klass ||= "application/#{params[:type]}".classify

end 

And it's occurrences now looks like this:

1. application_klass – just call this method to get a model name

2. application_klass.demodulize – using demodulize to split a string with ::

I've got rid of unnecessary constantize method, which is quite inefficient: just imagine that your application tries to find a constant in your project with the name specified in the string. See the benchmarks below to evaluate performance gains:

counter = 100_000

type = 'Rental'



Benchmark.bm(30) do |x|

  x.report('demodulize: ')                   { counter.times { "application/#{type}".classify.demodulize } }

  x.report('constantize.model_name.human: ') { counter.times { "application/#{type}".classify.constantize.model_name.human } }

end



                                     user     system      total        real

demodulize:                      3.560000   0.760000   4.320000 (  4.381891)

constantize.model_name.human:    8.500000   0.070000   8.570000 (  8.601007)