code: function baseDifference(array, values) {
      var index = -1,
          indexOf = getIndexOf(),
          length = array ? array.length : 0,
          result = [];
  
      while (++index < length) {
        var value = array[index];
        if (indexOf(values, value) < 0) {
          result.push(value);
        }
      }
      return result;
    }
docs: The base implementation of `_.difference` that accepts a single array
  of values to exclude.
  
  @private
  @param {Array} array The array to process.
  @param {Array} [values] The array of values to exclude.
  @returns {Array} Returns a new array of filtered values.