Quiz, challenge, js, why?,

Question

Can someone help and tell me why the output of the code below is 7 ?
----------------------------------------------------------
function abc(a){ return(function(y) { return y+1; })
(++a)+a;
}
alert(abc(2));

Answer 1

I just didn't know why the returned function is executed...

Answer 2

++2 gives 3, so value of a is now 3.
3+3+1 = 7

Answer 3

You execute your function in return statement.

(function(y){
y+1;
})(++a) // ++a is an argument of your function

You execute it with ++a. Preincrementation works before going into function hence "a" is 3. Then function adds 3+1 which is 4 and then abc function returns result of inner function and adds a, so it gives 4 + 3.

Answer 4

As Jakub said above 😄
you can review this lesson if you want..
https://www.sololearn.com/learn/JavaScript/1130/
Good luck my friend 💚