diff --git a/react-packager/src/Bundler/index.js b/react-packager/src/Bundler/index.js
index eb5039a7..97fd41ce 100644
--- a/react-packager/src/Bundler/index.js
+++ b/react-packager/src/Bundler/index.js
@@ -179,7 +179,10 @@ class Bundler {
       }
     }
 
-    const transformCacheKey = cacheKeyParts.join('$');
+    const transformCacheKey = crypto.createHash('sha1').update(
+      cacheKeyParts.join('$'),
+    ).digest('hex');
+
     this._cache = new Cache({
       resetCache: opts.resetCache,
       cacheKey: transformCacheKey,