diff --git a/esm.js b/esm.js
index c40a413..a5b1ea3 100644
--- a/esm.js
+++ b/esm.js
@@ -2,7 +2,7 @@
 
 module.exports = {
   rules: {
-    'import/extensions': 0,
+    'import/extensions': ['error', 'always'],
   },
   extends: ['@wfcd'],
   parser: '@babel/eslint-parser',
@@ -13,7 +13,11 @@ module.exports = {
       modules: true,
     },
     babelOptions: {
-      plugins: ['@babel/plugin-proposal-class-properties', '@babel/plugin-proposal-private-methods'],
+      plugins: [
+        '@babel/plugin-proposal-class-properties',
+        '@babel/plugin-proposal-private-methods',
+        '@babel/plugin-syntax-import-assertions',
+      ],
     },
   },
 };
diff --git a/package.json b/package.json
index a56f021..a754057 100644
--- a/package.json
+++ b/package.json
@@ -34,6 +34,7 @@
     "@babel/eslint-parser": "^7.19.1",
     "@babel/plugin-proposal-class-properties": "^7.18.6",
     "@babel/plugin-proposal-private-methods": "^7.18.6",
+    "@babel/plugin-syntax-import-assertions": "^7.20.0",
     "@babel/preset-env": "^7.19.1",
     "@typescript-eslint/eslint-plugin": "^5.38.0",
     "@typescript-eslint/parser": "^5.38.0",