add babel

package.json

@@ -30,7 +30,10 @@
     "object-hash": "^2.2.0"
   },
   "devDependencies": {
+    "@babel/core": "^7.16.7",
+    "@babel/preset-env": "^7.16.7",
     "ava": "^4.0.1",
+    "babel-loader": "^8.2.3",
     "c8": "^7.11.0",
     "copy-webpack-plugin": "^10.2.0",
     "eslint": "^8.6.0",

source/changelog.txt

@@ -1,5 +1,6 @@
 ### [Unreleased]
 #### Added
+- Add support for older browsers using babel
 #### Changed
 - Confirm compatibility with WordPress 5.9
 - Update dependencies

webpack.config.cjs

@@ -11,6 +11,20 @@ module.exports = {
     filename: 'events-loader.js',
     path: path.resolve(__dirname, 'build/' + '/front'),
   },
+  module: {
+    rules: [
+      {
+        test: /\.m?js$/,
+        exclude: /node_modules/,
+        use: {
+          loader: 'babel-loader',
+          options: {
+            presets: [['@babel/preset-env', { targets: 'defaults' }]],
+          },
+        },
+      },
+    ],
+  },
   plugins: [
     new CopyPlugin({
       patterns: [