Allow initializing enummer with hash

Gemfile

@@ -15,5 +15,5 @@ group :test do
   gem "sqlite3", "~> 1.4"
   gem "mysql2"
   gem "simplecov", require: false
-  gem 'simplecov-cobertura', require: false
+  gem "simplecov-cobertura", require: false
 end

README.md

@@ -33,6 +33,18 @@ Now set up enummer with the available values in your model:
 enummer permissions: %i[read write execute]
 ```
 
+Similar to `enum`, enummer can also be initialized with a hash, where the numeric index represents the position of the bit that maps to the flag:
+
+``` ruby
+enummer permissions: {
+  read: 0,
+  write: 1,
+  execute: 2
+}
+```
+
+This makes it easier to add/remove entries without worrying about migrating historical data.
+
 ### Scopes
 
 Scopes will now be provided for `<option>` and `not_<option>`.

enummer.gemspec

@@ -20,6 +20,6 @@ Gem::Specification.new do |spec|
     Dir["{app,config,db,lib}/**/*", "MIT-LICENSE", "Rakefile", "README.md"]
   end
 
-  spec.required_ruby_version = '>= 2.7'
+  spec.required_ruby_version = ">= 2.7"
   spec.add_dependency "rails", ">= 7.0.0"
 end

lib/enummer/enummer_type.rb

@@ -4,25 +4,24 @@
 
 module Enummer
   class EnummerType < ::ActiveRecord::Type::Value
-    # @param [Array<Symbol>] value_names list of all possible values for this type
-    def initialize(value_names:)
-      @value_names = value_names
-      @bit_pairs = determine_bit_pairs(value_names)
+    # @param [Array<Symbol>] values hash with bit-value pairs for all possible values for this type
+    def initialize(values:)
+      @values = values
     end
 
     # @return Symbol Representation of this type
     # @example
     #   :enummer[read|write|execute]
     def type
-      "enummer[#{@value_names.join("|")}]".to_sym
+      :"enummer[#{@values.keys.join("|")}]"
     end
 
     # @param [Symbol|Array<Symbol>] value Current value represented as one or more symbols
     # @return Numeric Numeric representation of values
     def serialize(value)
       return unless value
 
-      Array.wrap(value).sum { |value_name| @bit_pairs.fetch(value_name.to_sym, 0) }
+      Array.wrap(value).sum { |value_name| @values.fetch(value_name, 0) }
     end
 
     # @param [Numeric] value Numeric representation of values
@@ -31,19 +30,17 @@ def deserialize(value)
       return [] unless value
       return [] if value.to_i.zero?
 
-      @bit_pairs.each_with_object([]) do |(pair_name, pair_value), value_names|
+      @values.each_with_object([]) do |(pair_name, pair_value), value_names|
         next if (value & pair_value).zero?
 
         value_names << pair_name
       end
     end
 
-    private
-
-    def determine_bit_pairs(value_names)
-      value_names.map.with_index do |name, shift|
-        [name, 1 << shift]
-      end.to_h
+    # @param [Array<Symbol>] value Current value represented as one or more symbols or strings
+    # @return [Array<Symbol>] Current value represented as symbols
+    def cast(value)
+      Array.wrap(value).map(&:to_sym)
     end
   end
 end

lib/enummer/extension.rb

@@ -13,44 +13,43 @@ def enummer(values)
       options[:_suffix] = values.delete(:_suffix)
 
       name, values = values.first
+      values = _enummer_determine_bit_pairs(values)
 
-      attribute(name, :enummer, value_names: values)
+      attribute(name, :enummer, values: values)
 
-      singleton_class.__send__(:define_method, name) { values }
+      singleton_class.__send__(:define_method, name) { values.keys }
 
       _enummer_build_with_scope(name, values)
       _enummer_build_values(name, values, options)
     end
 
     private
 
-    def _enummer_build_with_scope(attribute_name, value_names)
+    def _enummer_build_with_scope(attribute_name, values)
       scope "with_#{attribute_name}", lambda { |desired|
-        expected = Array.wrap(desired).sum(0) { |value| 1 << value_names.index(value.to_sym) }
+        expected = Array.wrap(desired).sum(0) { |value| values[value.to_sym] }
 
         where("#{attribute_name} & :expected = :expected", expected: expected)
       }
     end
 
-    def _enummer_build_values(attribute_name, value_names, options)
-      value_names.each_with_index do |name, i|
+    def _enummer_build_values(attribute_name, values, options)
+      values.each do |name, bit|
         method_name = _enummer_method_name(attribute_name, name, options)
 
-        define_method("#{method_name}?") { self[attribute_name].include?(name) }
-        define_method("#{method_name}=") do |new_value|
+        define_method(:"#{method_name}?") { self[attribute_name].include?(name) }
+        define_method(:"#{method_name}=") do |new_value|
           if ActiveModel::Type::Boolean.new.cast(new_value)
             self[attribute_name] += [name]
           else
             self[attribute_name] -= [name]
           end
           self[attribute_name].uniq!
         end
-        define_method("#{method_name}!") do
+        define_method(:"#{method_name}!") do
           update(attribute_name => self[attribute_name] + [name])
         end
 
-        bit = 1 << i
-
         scope method_name, -> { where("#{attribute_name} & :bit = :bit", bit: bit) }
         scope "not_#{method_name}", -> { where("#{attribute_name} & :bit != :bit", bit: bit) }
       end
@@ -69,5 +68,12 @@ def _enummer_affix(attribute_name, value)
 
       value
     end
+
+    def _enummer_determine_bit_pairs(values)
+      values = values.map.with_index { |value, i| [value, i] }.to_h if values.is_a?(Array)
+      values.transform_values do |shift|
+        1 << shift
+      end
+    end
   end
 end

lib/tasks/enummer_tasks.rake

@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+
 # desc "Explaining what the task does"
 # task :enummer do
 #   # Task goes here

test/dummy/app/models/user.rb

@@ -4,7 +4,11 @@ class User < ApplicationRecord
   enummer permissions: %i[read write execute]
 
   enummer facial_features: %i[nose mouth eyes], _prefix: true
-  enummer diets: %i[cigarettes alcohol greens], _prefix: "consumes"
+  enummer diets: {
+    alcohol: 1,
+    cigarettes: 0,
+    greens: 2
+  }, _prefix: "consumes"
 
   enummer transport: %i[car truck submarine], _suffix: true
   enummer home: %i[box apartment house], _suffix: "home"

test/dummy/config/initializers/content_security_policy.rb

@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # Define an application-wide content security policy

test/dummy/config/initializers/inflections.rb

@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+
 # Be sure to restart your server when you modify this file.
 
 # Add new inflection rules using the following format. Inflections

test/dummy/config/initializers/permissions_policy.rb

@@ -1,4 +1,5 @@
 # frozen_string_literal: true
+
 # Define an application-wide HTTP permissions policy. For further
 # information see https://developers.google.com/web/updates/2018/06/feature-policy
 #

test/dummy/db/schema.rb

@@ -11,7 +11,6 @@
 # It's strongly recommended that you check this file into your version control system.
 
 ActiveRecord::Schema.define(version: 2022_01_30_163927) do
-
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
 
@@ -22,5 +21,4 @@
     t.integer "transport"
     t.integer "home"
   end
-
 end

test/enummer_test.rb

@@ -9,7 +9,7 @@ def setup
       diets: %i[cigarettes alcohol],
       transport: %i[submarine],
       home: %i[box])
-    @user2 = User.new(permissions: %i[read write])
+    @user2 = User.new(permissions: %i[read write], diets: %i[cigarettes])
     @user3 = User.new(permissions: %i[execute])
 
     [@user1, @user2, @user3].map { |user| user.save && user.reload }
@@ -32,7 +32,8 @@ def setup
   test "with_ scope returns users with all of those bits set" do
     assert_equal [@user1], User.with_permissions(%i[execute read write])
     assert_equal [@user1], User.with_permissions(%w[execute read write])
-    assert_equal [@user1, @user2], User.with_permissions(['read', :write])
+    assert_equal [@user1, @user2], User.with_permissions(["read", :write])
+    assert_equal [@user1, @user2], User.with_diets(%i[cigarettes])
   end
 
   test "not scopes return users without those bits set" do
@@ -76,9 +77,18 @@ def setup
   end
 
   test "setting the attribute with strings adds the values" do
-    @user3.update(permissions: ["read", "write"])
+    @user3.update(permissions: %w[read write])
 
     assert_equal %i[read write], @user3.permissions
+
+    updated = false
+    callback = lambda { |_name, _start, _finish, _id, payload| updated = true if payload[:sql].starts_with?("UPDATE") }
+
+    ActiveSupport::Notifications.subscribed(callback, "sql.active_record") do
+      @user3.update(permissions: %w[read write])
+    end
+
+    refute updated, "subsequent updates with the same values should be idempotent"
   end
 
   test "using a bang method properly updates the persisted field" do
@@ -106,7 +116,7 @@ def setup
   end
 
   test "recognizes boolean params" do
-    @user1.update!(ActionController::Parameters.new({"consumes_cigarettes"=>"false"}).permit(:consumes_cigarettes))
+    @user1.update!(ActionController::Parameters.new({"consumes_cigarettes" => "false"}).permit(:consumes_cigarettes))
     refute @user1.consumes_cigarettes?
   end
 

test/test_helper.rb

@@ -1,17 +1,17 @@
 # frozen_string_literal: true
 
-require 'simplecov'
+require "simplecov"
 SimpleCov.start do
   enable_coverage :branch
-  add_filter '/test/dummy/'
+  add_filter "/test/dummy/"
 
-  if ENV['CI']
-    require 'simplecov-cobertura'
+  if ENV["CI"]
+    require "simplecov-cobertura"
     SimpleCov.formatter = SimpleCov::Formatter::CoberturaFormatter
   end
 end
 
-  # Configure Rails Environment
+# Configure Rails Environment
 ENV["RAILS_ENV"] = "test"
 
 require_relative "../test/dummy/config/environment"