Early returns are a wonderful thing. They make your code readable and cases where the code can be cut short are clear.

They can also be overused in cases where a case statement would be preferred. Take this example:

def country_code(country)
  return "NL" if country == "Netherlands"
  
  "DE"
end

Rewritten using a case statement it reads much nicer:

def country_code(country)
  case country
  when "Netherlands" then "NL"
  else "DE"
end

This has a few other benefits as well:

  • Adding new cases is obvious, just add another when statement.
  • It exposes another issue: should the German case really be handled in the else? It's more clear to add an explicit when for it as well.
  • Preprocessing of the variable is easier, it only requires a change in one line of code.

It could evolve into something like this:

def country_code(country)
  case country.chomp
  when "Netherlands" then "NL"
  when "Germany" then "DE"
  when "France" then "FR"
end

Save the early return for more complex methods where non-trivial code paths can be skipped and cut short.