diff --git a/.eslintrc.js b/.eslintrc.js
index f5591b8..98e314d 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -26,6 +26,7 @@ module.exports = {
     'linebreak-style': ['error', 'unix'],
     'no-await-in-loop': 'off',
     'func-names': 0,
+    'arrow-parens': ['error', 'always'],
     'global-require': 0,
     'no-param-reassign': 'off',
     'no-continue': 'off',
diff --git a/esm.js b/esm.js
index fafad5e..b91ad7d 100644
--- a/esm.js
+++ b/esm.js
@@ -25,6 +25,7 @@ module.exports = {
     strict: ['error', 'safe'],
     'linebreak-style': ['error', 'unix'],
     'no-await-in-loop': 'off',
+    'arrow-parens': ['error', 'always'],
     'func-names': 0,
     'global-require': 0,
     'no-param-reassign': 'off',