Nuance local variable of counter in JavaScript

Consider the following code:

javascriptfunction test() {
  let num = 1;
  
  return function() {
    console.log(num);
    num++;
  };
}

test()(); //shows 1
test()(); //shows 1

Why will the number 1 always be displayed? In order to understand this, let's rewrite our code differently:

javascriptfunction test() {
  let num = 1;
  
  return function() {
    console.log(num);
    num++;
  };
};

let func1 = test(); // the first function
func1();  // shows 1

let func2 = test(); // the second function
func2();  // shows 1

That is, each function test call like this: test()() creates its own function with its own closure and immediately calls this function.

javascriptfunction func() {
  let num = 0;
  
  return function() {
    console.log(num);
    num++;
  };
};

func()();
func()();
func()();

javascriptfunction func() {
  let num = 0;
  
  return function() {
    console.log(num);
    num++;
  };
}

let test = func;

test()();
test()();
test()();