stacking returns items of null instead of empty arrays

in YAML this means no key/value instead of a key and a value of empty collection

package.json

@@ -91,5 +91,5 @@
 		"spellcheck": "find -type f \\( -name \"*.js\" -or -name \"*.md\" \\) ! -path \"./dist/*\" ! -path \"./dist/**/*\" ! -path \"./node_modules/**/*\" ! -path \"./test-coverage/**/*\" -exec npx cspell {} +",
 		"test": "npx jest --runInBand"
 	},
-	"version": "7.1.0"
+	"version": "7.2.0"
 }

stacking/createStackWhenIdentifierOrItemOrLevelOrAddWhenStack/index.js

@@ -40,8 +40,13 @@ module.exports =
 				targetLevelOrStack,
 			});
 
-		return getStackOrSingleLevelOrSingleItem(stackForTarget);
-
+		return (
+			stackForTarget.length
+			?
+			getStackOrSingleLevelOrSingleItem(stackForTarget)
+			:
+			null
+		);
 
 		function createExistingFactory() {
 			let hasExisting = false;

stacking/createStackWhenIdentifierOrItemOrLevelOrAddWhenStack/test.js

@@ -3,6 +3,18 @@ This library is free software, licensed under the terms of the GNU General Publi
 
 const createStackWhenIdentifierOrItemOrLevelOrAddWhenStack = require(".");
 
+test(
+	"Null and target of existing returns null.",
+	() =>
+		expect(
+			createStackWhenIdentifierOrItemOrLevelOrAddWhenStack({
+				identifierOrItemOrLevelOrStack: null,
+				targetLevelOrStack: [ "existing" ],
+			}),
+		)
+		.toBeNull(),
+);
+
 test(
 	"Identifier in target returns identifier.",
 	() =>