code: function(arrayA, arrayB) {
              var clone = slice.call(arrayA),
                  ln = clone.length,
                  i, j, lnB;
  
              for (i = 0,lnB = arrayB.length; i < lnB; i++) {
                  for (j = 0; j < ln; j++) {
                      if (clone[j] === arrayB[i]) {
                          erase(clone, j, 1);
                          j--;
                          ln--;
                      }
                  }
              }
  
              return clone;
          }
docs: Perform a set difference A-B by subtracting all items in array B from array A.
  
  @param {Array} arrayA
  @param {Array} arrayB
  @return {Array} difference