Scope, nested functions, called functions

Question

I’m studying that answer and I came across a doubt in a test that I am performing, follows :

<script>
function x(a1="a1"){          // "x" tem acesso a "a"
	var a2="a2";
	console.log("Consele fx =" + a1);
  	console.log("Consele fx =" + a2);
    function y(b1="b1"){      // "y" tem acesso a "a" e "b"
    	var b2="b2";
        console.log("Consele fy =" + a1);
        console.log("Consele fy =" + a2);
        console.log("Consele fy =" + b1);
        console.log("Consele fy =" + b2);
        function z(c1="c1"){  // "z" tem acesso a "a", "b", e "c"
       		var c2="c2";
            console.log("Consele fz =" + a1);
            console.log("Consele fz =" + a2);
            console.log("Consele fz =" + b1);
            console.log("Consele fz =" + b2);
            console.log("Consele fz =" + c1);
            console.log("Consele fz =" + c2);
        }
   }
}
x(10);
	//Consele fx =10
	//Consele fx =a2
y();//erro
z();//erro
</script>

So my doubts :

to) When calling the function x() everything inside shouldn’t be executed ?

b) How do I y() and z() be executed ?

c) How to change function parameters in the call ?

d) The error that gives is that the functions have not been defined, then as correctly define these function and parameters ?

Answer 1

to) When calling function x() everything inside should not be executed ?

no, when you call the function x within it is closed/declared function y. z never comes to be closed/declared y is not invoked/called. You would have to have y() or z() inside x, where the scope makes them accessible.

b) How I make y() and z() run ?

What causes a function to be invoked is (). You have to have it in the code y() inside x or z because it is only available in this scope (or within itself). To run z only within y or within itself, that function z is not available to the global scope nor x.

c) How to change function parameters in the call ?

just pass values in the arguments. For example: y(1), or y([123, 456]). If you use y(1) then the parameter b1 will have the value 1. This parameter b1 may have an automatic value if b1be it Undefined once you have in the statement: function y(b1 = "b1"){.

d) The error that gives is that the functions have not been defined, so how to correctly define these functions and parameters ?

they are correctly defined/declared, the problem is of scope as I mentioned in b), they do not exist in the eyes of the global scope, they are only available in the scope where they were declared and internal scopes to this.

---

function x(a1 = "a1") {
    var a2 = 'a2';

    function y(b1 = "b1") {
        var b2 = "b2";
        console.log("Consele fy =" + a1);
        console.log("Consele fy =" + a2);
        console.log("Consele fy =" + b1);
        console.log("Consele fy =" + b2);

        function z(c1 = "c1") {
            var c2 = "c2";
            console.log("Consele fz =" + a1);
            console.log("Consele fz =" + a2);
            console.log("Consele fz =" + b1);
            console.log("Consele fz =" + b2);
            console.log("Consele fz =" + c1);
            console.log("Consele fz =" + c2);
        }
        z(); // vai assumir "c1" pois o argumento é "undefined"
    }
    y('algo');
}
x(10);