diff --git a/bin/release-plan-setup.js b/bin/release-plan-setup.js
index 9f2c3c9..c77da0e 100755
--- a/bin/release-plan-setup.js
+++ b/bin/release-plan-setup.js
@@ -62,13 +62,12 @@ async function updatePackageJSON() {
     }
   }
 
+  pkg.devDependencies ||= {};
   pkg.devDependencies['release-plan'] = getDependencyRange(
     pkg.devDependencies['release-plan'],
     RELEASE_PLAN_VERSION
   );
 
-  pkg.devDependencies = pkg.devDependencies || {};
-
   let sortedPkg = sortPackageJson(pkg);
   let updatedContents = JSON.stringify(sortedPkg, null, 2);