diff --git a/rollup.config.js b/rollup.config.js
index 17911ff..b2eb00f 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -55,7 +55,7 @@ export default {
     json(),
     // To integrate Rollup and Babel.
     babel({
-      exclude: "node_modules/**",
+      exclude: /node_modules\/(?!immer)/,
       babelHelpers: "runtime",
     }),
     // To convert CommonJS modules to ES6.