diff --git a/examples/data-generator/src/finalize.js b/examples/data-generator/src/finalize.js
index a541ca14e9c..666a1a3f19b 100644
--- a/examples/data-generator/src/finalize.js
+++ b/examples/data-generator/src/finalize.js
@@ -15,7 +15,7 @@ export default function(db) {
     });
 
     // add 'collector' group
-    var customersBySpending = db.commands.reduce((customers, command) => {
+    const customersBySpending = db.commands.reduce((customers, command) => {
         if (!customers[command.customer_id]) {
             customers[command.customer_id] = { nbProducts: 0 };
         }
diff --git a/packages/ra-ui-materialui/src/layout/CardContentInner.js b/packages/ra-ui-materialui/src/layout/CardContentInner.js
index a04a641ef5d..d1acac4f83f 100644
--- a/packages/ra-ui-materialui/src/layout/CardContentInner.js
+++ b/packages/ra-ui-materialui/src/layout/CardContentInner.js
@@ -4,7 +4,7 @@ import classnames from 'classnames';
 import CardContent from '@material-ui/core/CardContent';
 import { makeStyles } from '@material-ui/core/styles';
 
-var useStyles = makeStyles(
+const useStyles = makeStyles(
     theme => ({
         root: {
             paddingTop: 0,