import { _includes } from "./_internal/_includes"

/**
 * Compares two lists of Strings/Numbers and returns the values that are in common (intersect) between the two lists
 *
 * @function
 * @name intersection
 * @param {Array<string> | Array<number>} arr1 An Array of Strings/Numbers
 * @param {Array<string> | Array<number>} arr2 An Array of Strings/Numbers
 * @returns {Array<string> | Array<number>} The values in common between the two lists
 */
function intersection(arr1, arr2) {
  const diff = []
  const len1 = arr1.length
  const len2 = arr2.length
  if (len1 === 0 || len2 === 0) return diff

  for (let i = 0; i < len1; i++) {
    const val = arr1[i]
    if (_includes(val, arr2)) {
      diff.push(val)
    }
  }
  for (let j = 0; j < len2; j++) {
    const val = arr2[j]
    if (_includes(val, arr1) && !_includes(val, diff)) {
      diff.push(val)
    }
  }
  return diff
}

export default intersection