diff --git a/lib/index.js b/lib/index.js
index 0aecbc4..dfc7b95 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -44,7 +44,7 @@ const ensureCachePath = co.wrap(function*() {
 
 module.exports = co.wrap(function*(name, opts = {}) {
   const outDir = yield ensureCachePath()
-  const parsed = name.split(',').map(parse)
+  let parsed = name.split(',').map(parse)
 
   // When you run `package-size ./dist/index.js,react`
   // Or `package-size react-dom,react --cwd`
@@ -240,7 +240,7 @@ module.exports = co.wrap(function*(name, opts = {}) {
     versionedName: parsed
       .map(
         pkg =>
-          `${pkg.name}${pkg.path ? `/${pkg.path}` : ''}@${packageInfo[pkg.name].version}`
+          `${pkg.name}${pkg.path ? `/${pkg.path}` : ''}${packageInfo[pkg.name] ? `@${packageInfo[pkg.name].version}` : ''}`
       )
       .join(','),
     size: asset.size - 2753, // minus webpack runtime size