diff --git a/package-lock.json b/package-lock.json
index 59f16b3..b9a4fd4 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -4004,9 +4004,9 @@
       }
     },
     "rollup-pluginutils": {
-      "version": "2.2.0",
-      "resolved": "https://registry.npmjs.org/rollup-pluginutils/-/rollup-pluginutils-2.2.0.tgz",
-      "integrity": "sha512-aqjTUCfZJK3O+TjH++PdQc8Lg6V6t/1Fhu8/6f3qPQzBt0xZruDgqblvb3RQOfKybTgfxKpyy2pQmQ4X2OmY4w==",
+      "version": "2.3.0",
+      "resolved": "https://registry.npmjs.org/rollup-pluginutils/-/rollup-pluginutils-2.3.0.tgz",
+      "integrity": "sha512-xB6hsRsjdJdIYWEyYUJy/3ki5g69wrf0luHPGNK3ZSocV6HLNfio59l3dZ3TL4xUwEKgROhFi9jOCt6c5gfUWw==",
       "requires": {
         "estree-walker": "^0.5.2",
         "micromatch": "^2.3.11"
diff --git a/package.json b/package.json
index 731b9de..d343db8 100644
--- a/package.json
+++ b/package.json
@@ -34,6 +34,6 @@
   "license": "MIT",
   "repository": "rollup/rollup-plugin-json",
   "dependencies": {
-    "rollup-pluginutils": "^2.2.0"
+    "rollup-pluginutils": "^2.3.0"
   }
 }
diff --git a/test/samples/form/customIndent.js b/test/samples/form/customIndent.js
index 0d6495f..abcaf9d 100644
--- a/test/samples/form/customIndent.js
+++ b/test/samples/form/customIndent.js
@@ -11,5 +11,6 @@ export default {
   "invalid-key": 1,
   nested: nested,
   array: array,
-  "function": "not used"
+  "function": "not used",
+  "null": null
 };
diff --git a/test/samples/form/default.js b/test/samples/form/default.js
index 1adb0f7..1eb3bae 100644
--- a/test/samples/form/default.js
+++ b/test/samples/form/default.js
@@ -11,5 +11,6 @@ export default {
 	"invalid-key": 1,
 	nested: nested,
 	array: array,
-	"function": "not used"
+	"function": "not used",
+	"null": null
 };
diff --git a/test/samples/form/input.json b/test/samples/form/input.json
index 2b03d67..f418783 100644
--- a/test/samples/form/input.json
+++ b/test/samples/form/input.json
@@ -5,5 +5,6 @@
     "subKey": "ok"
   },
   "array": [1, "2"],
-  "function": "not used"
+  "function": "not used",
+  "null": null
 }
diff --git a/test/samples/form/preferConst.js b/test/samples/form/preferConst.js
index 059d4b1..ab49d8f 100644
--- a/test/samples/form/preferConst.js
+++ b/test/samples/form/preferConst.js
@@ -11,5 +11,6 @@ export default {
 	"invalid-key": 1,
 	nested: nested,
 	array: array,
-	"function": "not used"
+	"function": "not used",
+	"null": null
 };