I have a `class File`, and constructor that accept `fullname` parameter. How can i prevent changing of this? I tried it with setter and getter, but it doesnt work

```js
class File {
  constructor(fullName) {
    this.fullName = fullName;
  }
  get fullname() {
    return this.fullname;
  }
  set fullname(newValue) {
    if (newValue) {
      newValue = this.fullName;
    }
  }

}

let example = new File("example.txt");
example.fullName = "modified.txt";
console.log(example.fullName); // should be example.txt
```