how to convert this block of code into a php version

  <script>

// Javascript program to check if all array elements are // same or not.

function areSame(arr)
{
    // Put all array elements in a HashSet
    let s = new Set(arr);

    // If all elements are same, size of
    // HashSet should be 1. As HashSet contains only distinct values.
    return (s.size == 1);
}
 
// Driver code
let arr=[1, 2, 3, 2];
if (areSame(arr))
        document.write("All Elements are Same");
    else
        document.write("Not all Elements are Same");

// This code is contributed by patel2127

Answer

Taking the information from the question previously dealt with here:

Check if all values in array are the same

I think your function would look like this:

function areSame(array $arr) : bool
{
    return(count(array_unique($arr)) === 1);
}

array_unique() returns the same array with all duplicates removed and count() counts the number of elements in an array.

If the array $arr only has one value after all duplicates are removed then all the values in the original array are unique.