Add deep to compact filter

lib/liquid/standardfilters.rb

@@ -530,7 +530,10 @@ def map(input, property, options = {})
     #   Removes any `nil` items from an array.
     # @liquid_syntax array | compact
     # @liquid_return [array[untyped]]
-    def compact(input, property = nil)
+    # @liquid_optional_param deep [boolean | string] Whether to use dot notation to perform a deep search. A string can be passed to change separator.
+    def compact(input, property = nil, options = {})
+      options = {} unless options.is_a?(Hash)
+      deep = deep_search_properties(property, options)
       ary = InputIterator.new(input, context)
 
       if property.nil?
@@ -539,7 +542,7 @@ def compact(input, property = nil)
         []
       else
         ary.reject do |item|
-          item[property].nil?
+          deep[:enable] ? item.dig(*deep[:properties]).nil? : item[property].nil?
         rescue TypeError
           raise_property_error(property)
         rescue NoMethodError

test/integration/standard_filter_test.rb

@@ -582,6 +582,45 @@ def test_compact_invalid_property
     end
   end
 
+  def test_compact_deep_default_separator
+    input = [
+      { "foo" => { "bar" => "baz", "handle" => "alpha" } },
+      { "foo" => { "handle" => "beta" } },
+      { "foo" => { "bar" => "qux", "handle" => "charlie" } },
+    ]
+    expectation = [
+      { "foo" => { "bar" => "baz", "handle" => "alpha" } },
+      { "foo" => { "bar" => "qux", "handle" => "charlie" } },
+    ]
+    assert_equal(expectation, @filters.compact(input, "foo.bar", { "deep" => true }))
+  end
+
+  def test_compact_deep_custom_separator
+    input = [
+      { "foo" => { "bar" => "baz", "handle" => "alpha" } },
+      { "foo" => { "handle" => "beta" } },
+      { "foo" => { "bar" => "qux", "handle" => "charlie" } },
+    ]
+    expectation = [
+      { "foo" => { "bar" => "baz", "handle" => "alpha" } },
+      { "foo" => { "bar" => "qux", "handle" => "charlie" } },
+    ]
+    assert_equal(expectation, @filters.where(input, "foo_bar", "baz", { "deep" => "_" }))
+  end
+
+  def test_compact_deep_off_by_default
+    input = [
+      { "foo.bar" => "baz", "handle" => "alpha" },
+      { "foo.handle" => "beta" },
+      { "foo.bar" => "qux", "handle" => "charlie" },
+    ]
+    expectation = [
+      { "foo.bar" => "baz", "handle" => "alpha" },
+      { "foo.bar" => "qux", "handle" => "charlie" },
+    ]
+    assert_equal(expectation, @filters.where(input, "foo.bar", "baz"))
+  end
+
   def test_reverse
     assert_equal([4, 3, 2, 1], @filters.reverse([1, 2, 3, 4]))
   end