Does the foreach method create a copy of the array on which it is launched is JS?

I think in some cases it is, but not in others.

The following JS code does not produce an infinite loop, I deduce that foreach creates a copy of the array when called

var li = [""]
li.forEach(() => {
    li.push("");
});

But the following code return "1 2 3 AA 5". Which shouldn't be the case if he had created a copy of the array. So why?

var li2 = [1,2,3,4,5]
li2.forEach((el) => {
    li2[3] = "AA";
  console.log(el)
});

Ty

"Does the foreach method create a copy of the array on which it is launched is JS?"

No, it doesn't. It iterates over the initial range of the original array. If the range/size of the array changes while iterating, it doesn't influence the iteration of the forEach.

It's similar to

<!-- begin snippet: js hide: false console: true babel: false -->

<!-- language: lang-js -->

function forEach(arr, cb) {
  for (let idx = 0, len = array.length; idx < len; ++idx) {
    cb(array[idx], idx, array);
  }
}

const array = [1, 2, 3];

forEach(array, (el, idx) => {
  array.push(el + idx);
});
console.log(array);

<!-- end snippet -->

but the actual implementation also skips empty slots in sparse arrays.