Javascript 【tricky】💡interview output questions (Part 2)

What is the output for each code mentioned below and Why ?

Add your solutions with explanation in the comment section.

Question 1

var y = 1;
  if (function f(){}) {
    y += typeof f;
  }
  console.log(y);

Question 2

var output = (function(x){
    delete x;
    return x;
  })(0);
  console.log(output);

Question 3

var Employee = {
  company: ’myCompany’
}
var emp1 = Object.create(Employee);
delete emp1.company
console.log(emp1.company);

Question 4

(function() {
   var a = b = 5;
})();
console.log(b);

Question 5

function test() {
   console.log(a);
   console.log(foo());
   var a = 1;
   function foo() {
return 2; }
}
test();

Comments

[Matt Ellen-Tsivintzeli]

damn. those are tricky!

[Matt Ellen-Tsivintzeli]

Now that I've looked into them, I understand all of them except for question 1. how is a function declaration legal in an if statement?

[Code Craft-Fun with Javascript]

Consider this -

console.log(typeof function f(){})

You will get its type as function. The function can be treated as a value , as in javascript everything is an object. Even functions are objects. Functions can be assigned to a variable as well.

let sum = (a,b) => a + b;

[Matt Ellen-Tsivintzeli]

OK. I think I get it. Because a function declaration can be on the RHS of an assignment statement it can go in the middle of an if statement?

[Code Craft-Fun with Javascript]

Checkout Part 1 as well !

[Acid Coder]

I failed all of them lol