static containsAll(arrA, arrB) {
    let containing = 0;

    for (let i = 0; i < arrA.length; i++) {
      for (let j = 0; j < arrB.length; j++) {
        if (arrA[i] === arrB[j]) {
          containing++;
        }
      }
    }

    return containing === arrB.length;
  }
Checks whether or not an array contains all the elements of another array, without regard to the order.

@static
@param {Array} arrA An array.
@param {Array} arrB An array.
@returns {Boolean} A boolean indicating whether or not both array contain the same elements.