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Code Craft-Fun with Javascript
Code Craft-Fun with Javascript

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

#javascript #webdev #frontend #beginners

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);
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Question 2 

var output = (function(x){ delete x; return x; })(0); console.log(output);
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Question 3 

var Employee = { company: ’myCompany’ } var emp1 = Object.create(Employee); delete emp1.company console.log(emp1.company);
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Question 4 

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

function test() { console.log(a); console.log(foo()); var a = 1; function foo() { return 2; } } test();
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Top comments (6)

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mellen profile image
Matt Ellen-Tsivintzeli •

damn. those are tricky!

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mellen profile image
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?

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codecraftjs profile image
Code Craft-Fun with Javascript • • Edited

Consider this -

console.log(typeof function f(){})
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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;
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mellen profile image
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?

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codecraftjs profile image
Code Craft-Fun with Javascript •

Checkout Part 1 as well !

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tylim88 profile image
Acid Coder •

I failed all of them lol