Selection Sort implemented in JavaScript (2 methods)

selection_sort.js

/* Selection sort works by selecting the minimum value in a list 
 * and swapping it with the first value in the list. It then 
 * starts at the second position, selects the smallest value in 
 * the remaining list, and swaps it with the second element. It 
 * continues iterating through the list and swapping elements 
 * until it reaches the end of the list.
 */

// METHOD 1: Using 2 `for` loops (ES5)
function selectionSort(array) {
  // Clone the array
  var arr = array.slice();

  // 1) Find the minimum value in the array
  // Loop through the arr
  for (var i = 0; i < arr.length; i++) {
    // Start off with the assumption that i is the index of the
    // minimum value in the arr
    var mindex = i;

    // Loop through the arr from after i to the end
    for (var j = i + 1; j < arr.length; j++) {
      // If there is another number that's less than arr[i]
      // or its successor minvals
      if (arr[j] < arr[mindex]) {
        // update the mindex
        mindex = j;
      }
    }
    
    // 2) Swap the minimum value with the item at index i
    // If arr[i] wasn't already the minimum value in for-j's scope
    if (i !== mindex) {
      // Swap the current item and the minimum value
      var tmp = arr[i];
      arr[i] = arr[mindex];
      arr[mindex] = tmp;
    }
  }

  // Return the sorted array
  return arr;
}

// METHOD 2: Use 1 `forEach` loop (ES6)
const selectionSort = array => {
  // Clone the array
  const arr = [...array];

  // Loop through the arr
  arr.forEach((n, i) => {
    // Find the minimum value from the current index to the end
    const scope = arr.slice(i);
    const minval = Math.min(...scope);

    // Save the index of the minval in the arr
    // Note the minval is in scope; do not indexOf out of scope
    // or you'll find duplicates
    const mindex = scope.indexOf(minval) + i;

    // If the current value is greater than the minimum value
    if (n > minval) {
      // Swap the two in place
      [arr[i], arr[mindex]] = [minval, n];
    }
  });

  // Return the sorted arr
  return arr;
};

// Tests
console.log(selectionSort([5, 3, 2, 1, 3])); // [ 1, 3, 3, 3, 5 ]
console.log(selectionSort([5, 3, 1])); // [ 1, 3, 5 ]
console.log(selectionSort([1, 4, 2, 8, 345, 123, 43, 32, 5643, 63, 123, 43, 2, 55, 1, 234, 92]));
// [ 1, 1, 2, 2, 4, 8, 32, 43, 43, 55, 63, 92, 123, 123, 234, 345, 5643 ]