amuntasim · February 8, 2018 03:49 · Feb 8, 2018
diff --git a/ruby_custom_flatten.rb b/ruby_custom_flatten.rb
@@ -0,0 +1,33 @@
+class FlattenTest
+  def self.custom_flatten(array, result = [])
+    array.each do |item|
+      if item.is_a? Array
+        custom_flatten(item, result)
+      else
+        result << item
+      end
+    end
+    result
+  end
+end
+
+RSpec.describe FlattenTest do
+
+  context '.custom_flatten' do
+    it 'should flatten array of arrays' do
+      expected = [1, 2, 3, 4, 5, 6]
+      expect(FlattenTest.custom_flatten([[1, 2], 3, [4, 5, 6]])).to eq expected
+    end
+
+    it 'should flatten nested array of arrays' do
+      expected = [1, 2, 3, 4, 5, 6, 7, 8, 9]
+      expect(FlattenTest.custom_flatten([[1, 2], 3, [4, 5, [6, [7, 8], 9]]])).to eq expected
+    end
+
+    it 'should return already flatten array' do
+      expected = [1, 2, 3, 4]
+      expect(FlattenTest.custom_flatten(expected)).to eq expected
+    end
+
+  end
+end