How to access outer function variable in nested inner function in JS

Question

I am new to JS and having a doubt with the below example. Please see the inline comments.

function outer() {
	var x = 5;
	console.log("outer",x); // Prints 5
	console.log("-----------");
	function inner() {
		var x = 6;
		console.log("inner",x); // Prints 6
		console.log("outer",x); // Prints 6. How to print 5
		console.log("-----------");
		function _inner() {
			var x = 7;
			console.log("_inner",x); // Prints 7
			console.log("inner",x); // Prints 7. How to print 6
			console.log("outer",x); // Prints 7. How to print 5
			console.log("-----------");
		}
		_inner();
	}
	inner();
}
outer();

Answer 1

May be this helps you. Assign your variables to your nested functions because therefore it is clear what varible should be used but they have to differ from each other in some way(name or via namespace):

function outer() {
    var x = 5;
    // or via namespace
    // var out = { x : 5 };
    console.log("outer",x); // 5
    console.log("-----------");
    function inner() {
        inner.x = 6;
        console.log("inner",inner.x); // 6
        console.log("outer",x); // 5
        console.log("-----------");
        function _inner() {
            _inner.x = 7;
            console.log("_inner",_inner.x); // 7
            console.log("inner",inner.x); // 6
            console.log("outer",x); // 5
            // namespace 
            // console.log("outer",out.x); // 5
            console.log("-----------");
        }
        _inner();
    }
    inner();
}
outer();

In this example only two of three varibles are assign(not outer x) to functions because otherwise you could assess outer.x from outside outer function and assign it any value:

function outer(){
   outer.x = 5;
   ...
}
// assign any value outside outer function
outer.x = 34;

But when a local variable is defined:

function outer(){
   var x = 23;
}

Then there is no chance to assign this local variable(x) any value from outside outer function.