Merge pull request #87 from MatzFan/ignore_keys

add ignore_keys options, fixes #86

.rubocop.yml

@@ -17,16 +17,24 @@ Metrics/BlockLength:
   Enabled: false
 Metrics/ModuleLength:
   Enabled: false
+Style/CaseLikeIf:
+  Enabled: false
 Style/Documentation:
   Enabled: false
 Style/FrozenStringLiteralComment:
   Enabled: true
   EnforcedStyle: always
+Style/OptionalBooleanParameter:
+  Enabled: false
 Style/NumericPredicate:
   Enabled: false
 Style/RedundantFreeze:
   Enabled: false
+Style/RedundantReturn:
+  Enabled: false
 RSpec/ExampleLength:
   Enabled: false
 RSpec/DescribeClass:
   Enabled: false
+RSpec/FilePath:
+  Enabled: false

Gemfile

@@ -4,5 +4,5 @@ source 'http://rubygems.org'
 gemspec
 
 group :test do
-  gem 'rake', '< 11'
+  gem 'rake'
 end

README.md

@@ -94,9 +94,8 @@ Hashdiff.unpatch!(b, diff).should == a
 
 ### Options
 
-There are eight options available: `:delimiter`, `:similarity`,
-`:strict`, `:indifferent`, `:numeric_tolerance`, `:strip`, `:case_insensitive`,
-`:array_path` and `:use_lcs`
+The following options are available: `:delimiter`, `:similarity`, `:strict`, `:ignore_keys`,
+`:indifferent`, `:numeric_tolerance`, `:strip`, `:case_insensitive`, `:array_path` and `:use_lcs`
 
 #### `:delimiter`
 
@@ -118,6 +117,26 @@ In cases where you have similar hash objects in arrays, you can pass a custom va
 
 The `:strict` option, which defaults to `true`, specifies whether numeric types are compared on type as well as value.  By default, an Integer will never be equal to a Float (e.g. 4 != 4.0).  Setting `:strict` to false makes the comparison looser (e.g. 4 == 4.0).
 
+#### `:ignore_keys`
+
+The `:ignore_keys` option allows you to specify one or more keys to ignore, which defaults to `[]` (none). Ignored keys are ignored at all levels. For example:
+
+```ruby
+a = { a: 1, b: { d: 2, a: 3 }, c: 4 }
+b = { a: 2, b: { d: 2, a: 7 }, c: 5 }
+diff = Hashdiff.diff(a, b, ignore_keys: :a)
+diff.should == [['~', 'c', 4, 5]]
+```
+If you wish instead to ignore keys at a particlar level you should 
+use a [custom comparison method](https://github.com/liufengyun/hashdiff#specifying-a-custom-comparison-method) instead. For example:
+
+```ruby
+a = { a: 1, b: { d: 2, a: 3 }, c: 4 }
+b = { a: 2, b: { d: 2, a: 7 }, c: 5 }
+diff = Hashdiff.diff(a, b) { |path, _e, _a| true if path == 'b.a' } # note '.' is the default delimiter
+diff.should == [['~', 'a', 1, 2], ['~', 'c', 4, 5]]
+``` 
+
 #### `:indifferent`
 
 The `:indifferent` option, which defaults to `false`, specifies whether to treat hash keys indifferently.  Setting `:indifferent` to true has the effect of ignoring differences between symbol keys (ie. {a: 1} ~= {'a' => 1})

changelog.md

@@ -1,5 +1,11 @@
 # Change Log
 
+* Add ignore_keys option (#86 @Matzfan)
+* Remove pinned version of rake < 11
+* Bump rspec dep ~> 3.5
+* Bump rubocop dep >= 1.52.1
+* Bump rubocop-rspec dep > 1.16.0
+
 ## v1.0.1 2020-02-25
 
 * Add indifferent option

hashdiff.gemspec

@@ -22,9 +22,9 @@ Gem::Specification.new do |s|
   s.homepage = 'https://github.com/liufengyun/hashdiff'
 
   s.add_development_dependency('bluecloth')
-  s.add_development_dependency('rspec', '~> 2.0')
-  s.add_development_dependency('rubocop', '~> 0.49.1') # last version that works with ruby 2.0
-  s.add_development_dependency('rubocop-rspec')
+  s.add_development_dependency('rspec', '~> 3.5')
+  s.add_development_dependency('rubocop', '>= 1.52.1') # earliest version that works with Ruby 3.3
+  s.add_development_dependency('rubocop-rspec', '> 1.16.0') # https://github.com/rubocop/rubocop-rspec/issues/461
   s.add_development_dependency('yard')
 
   if s.respond_to?(:metadata)

lib/hashdiff/compare_hashes.rb

@@ -26,6 +26,8 @@ def call(obj1, obj2, opts = {})
 
         result = []
 
+        opts[:ignore_keys].each { |k| common_keys.delete k }
+
         # add deleted properties
         deleted_keys.each do |k|
           k = opts[:indifferent] ? obj1_lookup[k] : k

lib/hashdiff/diff.rb

@@ -9,6 +9,7 @@ module Hashdiff
   # @param [Array, Hash] obj2
   # @param [Hash] options the options to use when comparing
   #   * :strict (Boolean) [true] whether numeric values will be compared on type as well as value.  Set to false to allow comparing Integer, Float, BigDecimal to each other
+  #   * :ignore_keys (Symbol, String or Array) [[]] a list of keys to ignore. No comparison is made for the specified key(s)
   #   * :indifferent (Boolean) [false] whether to treat hash keys indifferently.  Set to true to ignore differences between symbol keys (ie. {a: 1} ~= {'a' => 1})
   #   * :delimiter (String) ['.'] the delimiter used when returning nested key references
   #   * :numeric_tolerance (Numeric) [0] should be a positive numeric value.  Value by which numeric differences must be greater than.  By default, numeric values are compared exactly; with the :tolerance option, the difference between numeric values must be greater than the given value.
@@ -53,6 +54,7 @@ def self.best_diff(obj1, obj2, options = {}, &block)
   # @param [Array, Hash] obj2
   # @param [Hash] options the options to use when comparing
   #   * :strict (Boolean) [true] whether numeric values will be compared on type as well as value.  Set to false to allow comparing Integer, Float, BigDecimal to each other
+  #   * :ignore_keys (Symbol, String or Array) [[]] a list of keys to ignore. No comparison is made for the specified key(s)
   #   * :indifferent (Boolean) [false] whether to treat hash keys indifferently.  Set to true to ignore differences between symbol keys (ie. {a: 1} ~= {'a' => 1})
   #   * :similarity (Numeric) [0.8] should be between (0, 1]. Meaningful if there are similar hashes in arrays. See {best_diff}.
   #   * :delimiter (String) ['.'] the delimiter used when returning nested key references
@@ -81,6 +83,7 @@ def self.diff(obj1, obj2, options = {}, &block)
       similarity: 0.8,
       delimiter: '.',
       strict: true,
+      ignore_keys: [],
       indifferent: false,
       strip: false,
       numeric_tolerance: 0,
@@ -90,6 +93,8 @@ def self.diff(obj1, obj2, options = {}, &block)
 
     opts[:prefix] = [] if opts[:array_path] && opts[:prefix] == ''
 
+    opts[:ignore_keys] = [*opts[:ignore_keys]] # splat covers single sym/string case
+
     opts[:comparison] = block if block_given?
 
     # prefer to compare with provided block

spec/hashdiff/diff_spec.rb

@@ -49,6 +49,21 @@
     diff.should == []
   end
 
+  context 'with the ignore_keys option' do
+    a = { a: 1, b: { d: 2, a: 3 }, c: 4 }
+    b = { a: 2, b: { d: 2, a: 7 }, c: 5 }
+
+    it 'ignores a single key' do
+      diff = described_class.diff(a, b, ignore_keys: :a)
+      diff.should == [['~', 'c', 4, 5]]
+    end
+
+    it 'ignores an array of keys' do
+      diff = described_class.diff(a, b, ignore_keys: %i[a c])
+      diff.should == []
+    end
+  end
+
   it 'ignores string vs symbol differences, when indifferent is true' do
     diff = described_class.diff({ 'a' => 2, :b => 2 }, { :a => 2, 'b' => 2, :c => 3 }, indifferent: true)
     diff.should == [['+', 'c', 3]]