Question

In Sinatra application I have a code

gef '/123' do
  @var1 = # some calculations
  @var2 = # some calculations
  #..... many of them

  haml(:"view123")
end

and all of the instance variables are used in view123. I wonder, will there be any benefit of using the hash instead of many variables like this:

gef '/123' do
  hash_var = {}
  hash_var[:var1] = # some calculations
  hash_var[:var2] = # some calculations
  #..... many of them

  haml(:"view123")
end

Answer 1

I think you are on the right track, and it’s hard to advise in this very abstract sense, but in general that # some calculations looks like business logic. And business logic belongs in models.

How about a model instead? Make a new class that performs these calculations, then instantiate it and pass the instance to your view. Your controller/route handler remains lean and clean, and many many lines of calculations are all tucked into a file dedicated to just that thing. Neat and tidy.

get '/123' do
  @calc = CrazyCalculator.new
  haml(:view123)
end

view123.erb:

<ul>
  <li>Calc1: <%= @calc.calc1 %></li>
  <li>Calc2: <%= @calc.calc2 %></li>
  <li>Calc3: <%= @calc.calc3 %></li>
  <li><!-- many other calculation methods --></li>
</ul>