February 27, 2020 Ruby

Don't use early returns to handle simple cases

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.

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