Functions

Question 1

does all functions return a value?

Answer 1

Yes, by default it is undefined…. if the function return something, then it might be anything else.

Question 2

How to access an argument of a function that does not declare any parameter?

Answer 2

via arguments[]

Question 3

What is an Immediately Invoked Function Expression (IIFE)? How to declare it?

Answer 3

it is a function that is called right after declared. Declared via:

(function () {code here}();

Question 4

What is a Closure?

Answer 4

It is when the function returns a function. e.g:

function sum(a, b) {
  return function suminternally() {
   return a+b;
}
}

let mysum = sumb(1,2);
mysumn(); //returns 3

Question 5

When Arrow Functions were introduced?

Answer 5

ES6

Question 6

Why using arrow functions?

Answer 6

Shorter syntax

Question 7

How to declare an arrow function with and without params?

Answer 7

let af = param => {return param };
af('asd') // returns 'asd'

let af = () => {return 'asd'};
af() // returns 'asd'

Question 8

How to declare an arrow function that takes two or more params?

Answer 8

let af = (a, b) => {return a+b}

Question 9

Are arrow functions similar to c#’s lambda expressions?

Answer 9

Yes, same thing but with different names

Question 10

what happens to the this keyword when using arrow functions?

Answer 10

They are available but with a different scope (not the object scope). it is likely to be the Window object.