JSFiddle - React, Tailwind, and code Playground

JavaScript

let a = 10;

function parent(){
	let a = 2;
	neighbor();
	let child = function(){
		a++;
		alert('child(a): ' + a);
	}
	return child;
}

function neighbor(){
	alert('neighbor(a): '+a++);
}


let result=  parent();
result();
result();
result();
result();
result();