Reduce babel junk in built files

Configure babel preset-env to match the documentation's browser support
list.

configs/babel.config.js

@@ -1,15 +1,22 @@
-module.exports = function (api) {
-  if (api) {
-    api.cache(true);
-  }
-
-  let modules = false;
-
-  if (process.env.BABEL_ENV === 'commonjs' || process.env.NODE_ENV === 'test') {
-    modules = 'commonjs';
-  }
+const createConfig = ({ modules }) => {
+  const plugins = [
+    '@babel/plugin-transform-flow-strip-types',
+    ['@babel/plugin-proposal-class-properties', { loose: true }],
+    ['@babel/plugin-proposal-object-rest-spread', { useBuiltIns: true }],
+    '@babel/plugin-proposal-nullish-coalescing-operator',
+    [
+      '@babel/plugin-transform-runtime',
+      {
+        version: '7.18.6'
+      }
+    ]
+  ].concat(modules ? ['babel-plugin-add-module-exports'] : []);
 
   return {
+    assumptions: {
+      iterableIsArray: true
+    },
+    comments: true,
     presets: [
       [
         '@babel/preset-env',
@@ -19,18 +26,14 @@ module.exports = function (api) {
           exclude: ['transform-typeof-symbol'],
           targets: {
             browsers: [
-              'chrome 38',
-              'android 4',
-              'firefox 40',
-              'ios_saf 7',
-              'safari 7',
-              'ie 10',
-              'ie_mob 11',
-              'edge 12',
-              'opera 16',
-              'op_mini 12',
-              'and_uc 9',
-              'and_chr 38'
+              'chrome 49',
+              // https://www.mozilla.org/en-US/firefox/all/#product-desktop-esr
+              'firefox 91',
+              'ios_saf 10',
+              'safari 10',
+              // https://docs.microsoft.com/en-us/DeployEdge/microsoft-edge-support-lifecycle
+              'edge 94',
+              'opera 36'
             ]
           }
         }
@@ -38,17 +41,16 @@ module.exports = function (api) {
       '@babel/preset-react',
       '@babel/preset-flow'
     ],
-    plugins: [
-      '@babel/plugin-transform-flow-strip-types',
-      ['@babel/plugin-proposal-class-properties', { loose: true }],
-      ['@babel/plugin-proposal-object-rest-spread', { useBuiltIns: true }],
-      '@babel/plugin-proposal-nullish-coalescing-operator',
-      [
-        '@babel/plugin-transform-runtime',
-        {
-          version: '7.18.6'
-        }
-      ]
-    ].concat(modules ? ['babel-plugin-add-module-exports'] : [])
+    plugins: plugins
   };
 };
+
+module.exports = function (api) {
+  if (api) {
+    api.cache(true);
+  }
+
+  return process.env.BABEL_ENV === 'commonjs' || process.env.NODE_ENV === 'test'
+    ? createConfig({ modules: 'commonjs' })
+    : createConfig({ modules: false });
+};