Version Compare

VersionCompare simplifies comparison of version numbers with other version numbers. It aims to be as light and flexible as possible. Inputs can be a String, Integer, Float, Array, or any object that defines #to_comparable_version.

For simplicity's sake, Version Compare only works with up to four numeric values.

"<major>.<minor>.<tiny>.<patch>"
[<major>, <minor>, <tiny>, <patch>]

Add this line to your application's Gemfile:

gem "version_compare"

And then execute:

$ bundle

Or install it yourself as:

$ gem install version_compare

Tested MRI Ruby Versions:

• 2.2.10
• 2.3.7
• 2.4.4
• 2.5.1
• edge

VersionCompare has no other dependencies.

To get started, you can either use ComparableVersion.new(<value>) or ComparableVersion(<value>). To get the latter to work, you'll need to call include VersionCompare::Conversions in the class or context you're wanting to use it at.

class MyObject
  include VersionCompare::Conversions

  def my_method
    ComparableVersion(1) > ComparableVersion(2)
  end
end

MyObject.new.my_method  # => false

Or, to test on the Rails Console:

[1] pry(main)> include VersionCompare::Conversions  # => Object
[2] pry(main)> ComparableVersion(1.0) > ComparableVersion(1)  # => false

# - OR (without using `include VersionCompare::Conversions`) -

[1] pry(main)> VersionCompare::Conversions.ComparableVersion(1.0) > VersionCompare::Conversions.ComparableVersion(1)
# => false

ComparableVersion Compare uses the Comparable mix-in for comparisons, so you get all the usual operators:

include VersionCompare::Conversions

ComparableVersion(2) > ComparableVersion(1)                   # => true
ComparableVersion(1.2) > ComparableVersion(1.2)               # => false
ComparableVersion("1.2.3") >= ComparableVersion("1.2")        # => true
ComparableVersion("1.2.3.4") <= ComparableVersion("1.2.3.4")  # => true
ComparableVersion([1, 2]) == ComparableVersion(["1", "2"])    # => true
ComparableVersion("1.2.0.0") == ComparableVersion(1.2)        # => true
ComparableVersion("1.0.0.0") != ComparableVersion(1)          # => false

[
  ComparableVersion(1),
  ComparableVersion("1.0.0.1"),
  ComparableVersion(0.1)
].sort.map(&:to_s)
# => ["0.1", "1", "1.0.0.1"]

[
  ComparableVersion(1),
  ComparableVersion("1.0.0.1"),
  ComparableVersion(0.1)
].sort { |a, b| b <=> a }.map(&:to_s)
# => ["1.0.0.1", "1", "0.1"]

ComparableVersion() is a conversion function. It follows the Ruby convention of defining a conversion function that uses the same name as the class it represents, such as how Array() converts inputs to an Array object. Just like the standard Ruby conversion functions, ComparableVersion() tries its hardest to convert any ComparableVersion-like input into a new ComparableVersion object. Given a numeric, string, or array input (which are all obvious conversions to make), ComparableVersion() is essentially the same as ComparableVersion.new(). However, ComparableVersion() is otherwise a little more strict in that if you pass in an object that doesn't reasonably look like a ComparableVersion it will raise a TypeError. Doing the same for ComparableVersion.new() will ultimately just #to_s the input and, since almost every object responds to #to_s, the result is that you may end up with a 0 version.

VersionCompare::ComparableVersion.new(OpenStruct.new(a: 1)).to_s  # => "0"

But of course! All you have to do is define a #to_comparable_version implicit conversion method in your object that creates a new ComparableVersion object in the usual fashion.

class MyObject
  VERSION = 1.9

  def to_comparable_version
    VersionCompare::ComparableVersion.new(VERSION.to_s)
  end
end

include VersionCompare::Conversions

ComparableVersion(MyObject.new) > ComparableVersion(2.0)  # => false

Because, objects should be open for extension, but closed for modification.

# Given a Rails app:

# /config/application.rb
module MyRailsApp
  class Application < Rails::Application
    # ...

    VERSION = "1.2".freeze

    def to_comparable_version
      VersionCompare::ComparableVersion.new(VERSION)
    end
  end
end

# Now, from the context of that Rails app you can call:
include VersionCompare::Conversions

ComparableVersion(Rails.application) > ComparableVersion(1.0)  # => true

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/pdobb/version_compare.

The gem is available as open source under the terms of the MIT License.