JavaScript-scope-playground.js

var outerFunction = function(){
 
   if(true){
      var x = 5;
      //console.log(y); //line 1, ReferenceError: y not defined
   }
 
   var nestedFunction = function() {
 
      if(true){
         var y = 7;
         console.log("2: x is %O", x); //line 2, x will still be known prints 5
      }
 
      if(true){
        console.log("3: y is %O", y); //line 3, prints 7
       }
   }
   console.log("call nestedFunction before returning it");
   nestedFunction();
   console.log("change x")
   x = 6;
   return nestedFunction;
}
 
var myFunction = outerFunction();
console.log("call the nestedFunction we got");
myFunction();



// playground for observing that this is not lexical

var person = {
 
  name: "Alice",
  age: 42,
 
  showInfo: function() {
    console.log("1 -- Name:", this.name, " Age:", this.age);
 
    nestedFunction = function() {
      console.log("2 -- Name:", this.name, " Age:", this.age);
      console.log("2 -- this: %O", this);
    }
 
    nestedFunction();
   }
}
person.showInfo();