feat: Refactor codebase, improve types, attempt test fixes

babel.config.cjs

@@ -1,9 +1,27 @@
-module.exports = {
-  presets: [
+module.exports = (api) => {
+  // Check if running in test environment (NODE_ENV is set to 'test' by run-tests.js)
+  const isTest = api.env('test');
+
+  const presets = [
     ['@babel/preset-env', { targets: { node: 'current' } }],
     '@babel/preset-typescript',
-  ],
-  plugins: [
-    ['@babel/plugin-transform-modules-commonjs']
-  ]
+  ];
+
+  const plugins = []; // Keep only one declaration
+
+  // Only add the CJS transform plugin if NOT in test environment
+  if (!isTest) {
+    plugins.push(['@babel/plugin-transform-modules-commonjs']);
+  }
+
+  // For Jest (test environment), ensure node_modules are not completely ignored
+  // if needed, but rely on transformIgnorePatterns in jest.config.cjs primarily.
+  // This is more of a fallback if transformIgnorePatterns isn't sufficient.
+  const ignore = isTest ? [] : [/node_modules/]; 
+
+  return {
+    presets,
+    plugins,
+    ignore, // Add ignore configuration back
+  };
 };