Consider the following code.
const l_array = ['a', 'b', 'c'];
const l_it = l_array[Symbol.iterator](); //convert to iterator
var result = Array.from(l_it);
When that code is called from JavaScript's native Array.from, the result is ['a', 'b', 'c']
When that function is called from prototype.js Array.from, the result is []
https://github.com/prototypejs/prototype/blob/master/src/prototype/lang/array.js