如何将JS常量变量编译成浏览器友好的代码，使其成为只读的？

const PI = 3.14159;

const obj = Object.freeze({ name: 'John', age: 30 });
obj.name = 'Mike'; // 无效，无法修改属性值

const createCounter = () => {
  let count = 0;
  return {
    getCount: () => count,
  };
};

const counter = createCounter();
console.log(counter.getCount()); // 输出0
counter.count = 10; // 无效，无法修改count变量

const counter = (() => {
  let count = 0;
  return {
    getCount: () => count,
  };
})();

console.log(counter.getCount()); // 输出0
counter.count = 10; // 无效，无法修改count变量