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]
```

1 files changed, 44 insertions, 0 deletions

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