@vanillaes/computer-science/src/Sort/InsertionSort.js

Algorithms and Data Structures implemented in modern JS

/**
 * A InsertionSort algorithm
 *
 * The sort maintains a sorted (left) and unsorted (right) sections. As each
 * value is checked, if it's greater than the previous value it gets swapped
 * to the left until it is no longer greater.
 *
 * @export
 * @param {*[]} array the input array
 * @param {Function} [comparator] a function to compare 2 values (defaults asc->desc)
 * @param {Function} [step] an optional function that gets applied at each step
 * @returns {*[]} the sorted array
 */
function InsertionSort (array, comparator = (a, b) => a < b, step) {
  const N = array.length
  for (let i = 1; i < N; i++) {
    for (let j = i; j > 0; j--) {
      if (comparator(array[j], array[j - 1])) {
        [array[j], array[j - 1]] = [array[j - 1], array[j]]
      }
    }
    if (step) { step(array) }
  }

  return array
}

export { InsertionSort }