Bubble Sort JS

bubblesort.js

function bubbleSort(arr){
  //start the endIndex at the last index of the array
    let endIndex = arr.length - 1;
  //run the loop until the endIndex(sorted portion) is the 0 (the full array)
    while(endIndex > 0){
        // count the number of swaps to short circuit the loop if it is already sorted
        let swaps = 0;
        //reset the currentIndex to the beginning of the array each time a new element is sorted
        let currentIndex = 0;
        // loop over the array, comparing each pair of elements until the comparison element reaches the sorted portion of the array
        while(currentIndex < endIndex){
            // uncomment this line to see the comparison in action
            // console.log(arr, arr[currentIndex], arr[currentIndex + 1])
            // if the current element is greater than the element in front of it
            if(arr[currentIndex] > arr[currentIndex + 1]){
                //swap the 2 elements using our helper function
                swap(arr, currentIndex, currentIndex + 1);
                // add 1 to the swaps counter
                swaps++;
            }
            //increase the currentIndex to continue iterating through the array
            currentIndex++;
        }
        //stop the loop if there were no swaps because the array must be already sorted 
        if(swaps === 0) break;
        // subtract the endIndex number to account for the new element added to the array
        endIndex--;

    }

    return arr;
}