export class A {

   echo() {
     console.log('a');
   }
}

{
  "compilerOptions": {
    "lib": ["es2017", "dom"],
    "target": "es5",
    "module": "commonjs",
  },
}

class A {
   echo() {
      console.log('a');
   }
}

if (typeof window !== 'undefined') {
   window.A = A
} else {
   Object.defineProperty(exports, "__esModule", { value: true });
   exports.A = A;
}