diff --git a/jest.config.js b/jest.config.cjs
similarity index 92%
rename from jest.config.js
rename to jest.config.cjs
index 5b43d379d..88d0a0c9e 100644
--- a/jest.config.js
+++ b/jest.config.cjs
@@ -7,7 +7,7 @@ module.exports = {
   transform: {
     '^.+\\.[jt]sx?$': 'esbuild-jest',
     '^.+\\.jison$': [
-      path.resolve(__dirname, './src/jison/transformer.js'),
+      path.resolve(__dirname, './src/jison/transformer.cjs'),
       { 'token-stack': true },
     ],
   },
diff --git a/src/jison/transformer.js b/src/jison/transformer.cjs
similarity index 100%
rename from src/jison/transformer.js
rename to src/jison/transformer.cjs