Javascript I need help Arrays

Question

var arr = [1,2,3,4];
arr[arr[1]] = 5;
console.log(arr)

Why this code is
// 1,2,5,4
Inistead of
// 1,5,3,4

I need help

Answer 1

arr = [1,2,3,4];
|
Index 0,1,2,3

arr[ 1 ] == 2 right ?

So

arr[ arr[1] ] == arr[ 2 ]

Finally we set index 2 = 5
arr[ 2 ] = 5

We have
arr = [1,2,5,4];
|
Index 0,1,2,3

Answer 2

arr[1] = 2
arr[arr[1]] = arr[2]
Finally:
arr[2] = 5

The array starts from 0. (0 is the first element

arr[0] = 1
arr[1] = 2
...
arr[3] = 4

Answer 3

Thanks i get it its can a tricky 😂

Answer 4

Pedro H.J 💚 Alex Tușinean 🍏 thanks guys... Had to stare at this for awhile until it all made sense lol 👍🏽