I have a function a where there is a function b that references foo in its closure.

class Foo {}

function a() {
  const foo = new Foo()
   const b = () => {
        foo // referencing `foo`
    }
    b()
};

a() // no memory leaks

after I executed a, there are no memory leaks for Foo.

I also tweaked it slightly. Still, no memory leaks for the following examples.

class Foo {}

function a() {
  const foo = new Foo()
   const b = () => {
        if(foo === 'foo') {
            
        }
    }
    b()
};
a() // no memory leaks

class Foo {}

function a() {
  const foo = new Foo()
   const b = () => {
        console.log(foo.lol)
    }
    b()
};
a() // no memory leaks

But as soon as I logged out foo, it causes memory leaks.

class Foo {}

function a() {
  const foo = new Foo()
   const b = () => {
        console.log(foo)
    }
    b()
};
a() // memory leaks

My question is why console.log(fii) leaks but referencing foo in other ways or log out its property console.log(foo.lol)

I tested these in Chrome 103 DevTool console.