function hello() {
  console.log(this); // Object [global] { ... }
  console.log(this === global); // true
}
hello();
class helloClass {
  num = 1;
  
  inHello() {
    console.log(this); // helloClass { num: 1 }
    console.log(this === global); // false
  }
}

const hc = new helloClass();
hc.inHello();
console.log(this); // {}
console.log(this === module.exports); // true