Bubble Sort in Javascript

function bubbleSort(array) {
  let n = array.length
  while (n > 0) {
    let lastModifiedIndex = 0
    for (let currentIndex = 1; currentIndex < n; currentIndex++) {
      // if the item at the previous index is greater than the item at the `currentIndex`, swap them
      if (array[currentIndex - 1] > array[currentIndex]) {
        // swap
        let temp = array[currentIndex - 1]
        array[currentIndex - 1] = array[currentIndex]
        array[currentIndex] = temp
        // save the index that was modified
        lastModifiedIndex = currentIndex
      }
    }
    // save the last modified index so we know not to iterate past it since all proceeding values are sorted
    n = lastModifiedIndex
  }
}

let array = [12, 11, 15, 10, 9, 1, 2, 3, 13, 14, 4, 5, 6, 7, 8]
bubbleSort(array)
alert(array)