diff --git a/jest.config.js b/jest.config.js
index bfe8eb1fb..8dfc1a2bc 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -18,7 +18,7 @@ if (INSTALL_PACKAGE || (isProduction && !TEST_STANDALONE)) {
 process.env.PRETTIER_DIR = PRETTIER_DIR;
 
 const testPathIgnorePatterns = [];
-let transform;
+let transform = {};
 if (TEST_STANDALONE) {
   testPathIgnorePatterns.push("<rootDir>/tests_integration/");
 }