Interview4: Hoisting & Dead Zone in Javascript

Deep Dive into Hoisting & Dead Zone in Javascript

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You have read the Hoisting in JS and would like to solve hard questions of it. Here you go, the article will deep dive into the Hoisting concepts of Javascript. If you have any doubt, feel free to comment and expect a quick response.

Let’s start with a some simple example.

Question1:

function userData() {
 return userData;
}

console.log(typeof userData()); 

Answer:

// Output: function;

Question2:

function foo() {
  let a = b = 0;
  a++;
  return a;
}

foo();

console.log(typeof a);
console.log(typeof b);

Answer:

undefined
number

Question3:

function foo(x) {
  x();
  function x() {
    console.log("foo");
  }
}

foo(function() {
  console.log("bar")
});

Answer:

foo

Question4:

let a = 10;
var b = 20;

console.log(a);
console.log(b);

console.log(window.a);
console.log(window.b);

console.log(this.a);
console.log(this.b);

Answer: