configured babel correctly

Author: bennobuilder

package.json

@@ -47,6 +47,9 @@
     "url": "git+https://github.com/agile-ts/agile.git"
   },
   "devDependencies": {
+    "@babel/cli": "^7.15.7",
+    "@babel/core": "^7.15.5",
+    "@babel/preset-env": "^7.15.6",
     "@changesets/cli": "^2.16.0",
     "@rollup/plugin-babel": "^5.3.0",
     "@rollup/plugin-node-resolve": "^13.0.4",

packages/rollup.config.default.js

@@ -8,19 +8,17 @@ import esbuild from 'rollup-plugin-esbuild';
 import typescript from '@rollup/plugin-typescript';
 import bundleSize from 'rollup-plugin-bundle-size';
 
-export const fileExtensions = ['.js', '.ts', '.tsx'];
+export const fileExtensions = ['.ts'];
 
 export function createEsbuildConfig(config) {
   config = {
     target: 'es2015',
-    tsconfig: path.resolve('./tsconfig.json'),
     additionalOptions: {},
     ...config,
   };
   return esbuild({
     minify: false,
     target: config.target,
-    tsconfig: config.tsconfig,
     ...config.additionalOptions,
   });
 }
@@ -73,8 +71,9 @@ export function createESMConfig(config) {
     external: config.external,
     plugins: [
       nodeResolve({ extensions: fileExtensions }),
-      createEsbuildConfig({ target: 'es2015', tsconfig: config.tsconfig }),
-      // typescript(), // Not required because the 'esbuild-config' does configure typescript for us
+      createEsbuildConfig({ target: 'es2015' }),
+      // typescript(), // Not required because esbuild takes care of configuring typescript
+      // babel(/* */), // Not required because esbuild takes care of converting ES2015+ modules into compatible JavaScript files
       !config.multiFileOutput && bundleSize(),
       ...config.additionalPlugins,
     ],
@@ -96,15 +95,22 @@ export function createCommonJSConfig(config) {
 
   return defineConfig({
     input: config.input,
-    output: { file: config.output, format: 'cjs' },
+    output: {
+      file: config.output,
+      format: 'cjs',
+    },
     external: config.external,
     plugins: [
       nodeResolve({ extensions: fileExtensions }),
+      // https://github.com/rollup/plugins/tree/master/packages/babel#running-babel-on-the-generated-code
       babel({
         babelHelpers: 'bundled',
         comments: false,
+        exclude: ['node_modules/**'],
+        presets: ['@babel/preset-env'],
+        extensions: fileExtensions, // https://github.com/rollup/rollup-plugin-babel/issues/255
       }),
-      typescript({ tsconfig: config.tsconfig }),
+      typescript(), // Only so that Rollup can work with typescript (Not for generating any 'declaration' files)
       bundleSize(),
       ...config.additionalPlugins,
     ],