Bubblesort in javascript can't run?

Question

Please can you tell me what is wrong to this implementation of bubble sort algorithm in JavaScript?

function bubbleSort(arr) {
  var swapped;
  do {
    swapped = false;
    for (var i = 0; i < arr.length - 1; i++) {
      if (arr[i] > arr[i + 1]) {
        var temp = arr[i];
        arr[i] = arr[i + 1];
        arr[i + 1] = temp;
        swapped = true;
      }
    }
  } while (swapped)
}


console.log(bubbleSort([4, 25, 1, 6, 2])); // [ 1, 2, 4, 6, 25 ]
console.log(bubbleSort([13, 1, 9, 38, 8, 3, 1])); // [ 1, 2, 4, 6, 25 ]

Answer 1

Your function will return undefined.You need to return arr from the function.

If you don't want to modify the original array then make a copy of original array using slice(). In the below case it doesnot matter because arrays are not stored in any variable.

function bubbleSort(arr) {
  arr = arr.slice()
  var swapped;
  do {
    swapped = false;
    for (var i = 0; i < arr.length - 1; i++) {
      if (arr[i] > arr[i + 1]) {
        var temp = arr[i];
        arr[i] = arr[i + 1];
        arr[i + 1] = temp;
        swapped = true;
      }
    }
  } while (swapped)
  
  return arr;
}


console.log(bubbleSort([4, 25, 1, 6, 2])); // [ 1, 2, 4, 6, 25 ]
console.log(bubbleSort([13, 1, 9, 38, 8, 3, 1])); // [ 1, 2, 4, 6, 25 ]