class ActiveModel::Type::Boolean

Active Model Type Boolean¶ ↑

A class that behaves like a boolean type, including rules for coercion of user input.

Values set from user input will first be coerced into the appropriate ruby type. Coercion behavior is roughly mapped to Ruby’s boolean semantics.

“false”, “f” , “0”, 0 or any other value in FALSE_VALUES will be coerced to false
Empty strings are coerced to nil
All other values will be coerced to true

Source

# File lib/active_model/type/boolean.rb, line 37
def cast_value(value)
  if value == ""
    nil
  else
    !FALSE_VALUES.include?(value)
  end
end