diff --git a/src/polyfills/mime-types.js b/src/polyfills/mime-types.js
index 42b2b95..5a61a0e 100644
--- a/src/polyfills/mime-types.js
+++ b/src/polyfills/mime-types.js
@@ -1,2 +1,2 @@
 // Stub
-exports.lookup = (file) => {};
\ No newline at end of file
+exports.lookup = (file) => 'text/plain';
\ No newline at end of file