Merge pull request #33137 from bogdanvlviv/add-array-extract-method

Add `Array#extract!`

4 files changed, 77 insertions, 0 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 25e2ee04f9..4ae02edd6a 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,14 @@
+*   Add `Array#extract!`.
+
+    The method removes and returns the elements for which the block returns a true value.
+    If no block is given, an Enumerator is returned instead.
+
+        numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+        odd_numbers = numbers.extract! { |number| number.odd? } # => [1, 3, 5, 7, 9]
+        numbers # => [0, 2, 4, 6, 8]
+
+    *bogdanvlviv*
+
 *   Support not to cache `nil` for `ActiveSupport::Cache#fetch`.
 
         cache.fetch('bar', skip_nil: true) { nil }
diff --git a/activesupport/lib/active_support/core_ext/array.rb b/activesupport/lib/active_support/core_ext/array.rb
index 6d83b76882..a2569c798b 100644
--- a/activesupport/lib/active_support/core_ext/array.rb
+++ b/activesupport/lib/active_support/core_ext/array.rb
@@ -3,6 +3,7 @@
 require "active_support/core_ext/array/wrap"
 require "active_support/core_ext/array/access"
 require "active_support/core_ext/array/conversions"
+require "active_support/core_ext/array/extract"
 require "active_support/core_ext/array/extract_options"
 require "active_support/core_ext/array/grouping"
 require "active_support/core_ext/array/prepend_and_append"
diff --git a/activesupport/lib/active_support/core_ext/array/extract.rb b/activesupport/lib/active_support/core_ext/array/extract.rb
new file mode 100644
index 0000000000..cc5a8a3f88
--- /dev/null
+++ b/activesupport/lib/active_support/core_ext/array/extract.rb
@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class Array
+  # Removes and returns the elements for which the block returns a true value.
+  # If no block is given, an Enumerator is returned instead.
+  #
+  #   numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+  #   odd_numbers = numbers.extract! { |number| number.odd? } # => [1, 3, 5, 7, 9]
+  #   numbers # => [0, 2, 4, 6, 8]
+  def extract!
+    return to_enum(:extract!) { size } unless block_given?
+
+    extracted_elements = []
+
+    reject! do |element|
+      extracted_elements << element if yield(element)
+    end
+
+    extracted_elements
+  end
+end
diff --git a/activesupport/test/core_ext/array/extract_test.rb b/activesupport/test/core_ext/array/extract_test.rb
new file mode 100644
index 0000000000..200727667c
--- /dev/null
+++ b/activesupport/test/core_ext/array/extract_test.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require "abstract_unit"
+require "active_support/core_ext/array"
+
+class ExtractTest < ActiveSupport::TestCase
+  def test_extract
+    numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+    array_id = numbers.object_id
+
+    odd_numbers = numbers.extract!(&:odd?)
+
+    assert_equal [1, 3, 5, 7, 9], odd_numbers
+    assert_equal [0, 2, 4, 6, 8], numbers
+    assert_equal array_id, numbers.object_id
+  end
+
+  def test_extract_without_block
+    numbers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
+    array_id = numbers.object_id
+
+    extract_enumerator = numbers.extract!
+
+    assert_instance_of Enumerator, extract_enumerator
+    assert_equal numbers.size, extract_enumerator.size
+
+    odd_numbers = extract_enumerator.each(&:odd?)
+
+    assert_equal [1, 3, 5, 7, 9], odd_numbers
+    assert_equal [0, 2, 4, 6, 8], numbers
+    assert_equal array_id, numbers.object_id
+  end
+
+  def test_extract_on_empty_array
+    empty_array = []
+    array_id = empty_array.object_id
+
+    new_empty_array = empty_array.extract! {}
+
+    assert_equal [], new_empty_array
+    assert_equal [], empty_array
+    assert_equal array_id, empty_array.object_id
+  end
+end