ksr-maybe
This gem provides a Maybe type. The Maybe type either contains a value
(represented as Just) or it is empty (represented as Nothing).
Installation
Install the ksr-maybe gem, or add it to your Gemfile with bundler:
# In your Gemfile
gem 'ksr-maybe'Usage
Maybe is useful for handling potentially null values:
User = Struct.new(:email, :name)
users = [
User.new("jane@doe.com", "Jane Doe"),
User.new("john@doe.com", "John Doe")
]
# When value is not null
user = users.find { |user| user.email == "jane@doe.com" }
Maybe.from_nullable(user)
.map { |user| user.name }
.get_or_else { "User not found" }
#=> "Jane Doe"
# When value is null
user = users.find { |user| user.email == "not@present.com" }
Maybe.from_nullable(user)
.map { |user| user.name }
.get_or_else { "User not found" }
#=> "User not found"Contracts
This gem utilizes the 'contracts.ruby' gem, which adds dynamic type-checking to the 'ruby-maybe' codebase. By default, the 'contracts.ruby' gem will raise an error during runtime upon a type mismatch. To override this error throwing behavior, see this 'contracts.ruby' documentation.