conditional_array.rb

# This option has the most clarity, but I generally hate local variables in a
# method, preferring to use tap.
def calculated_foo
  available_foos = []
  available_foos << bar
  available_foos << baz.qux if baz
  available_foos.max
end

# It's a little less clear, unless you know what tap is, and `end.max` is
# painful to look at.
def calculated_foo
  [].tap do |available_foos|
    available_foos << bar
    available_foos << baz.qux if baz
  end.max
end

# This avoids the painful `end.max` for a more-common `}.max`, but goes against
# the culture of using do/end for multi-line blocks.
def calculated_foo
  [].tap { |available_foos|
    available_foos << bar
    available_foos << baz.qux if baz
  }.max
end

# Perly
def calculated_foo
  ((baz ? [baz.qux] : []) + [bar]).max
end

# ternary? ? && : ||
def calculated_foo
  ((baz && [baz.qux] || []) + [bar]).max
end