text: 'use strict';
  
  module.exports = function (column) {
  
    var cls = this.opts.sortIcon.base + ' ';
  
    if (!this.sortable(column)) return;
  
    if (this.hasMultiSort && this.orderBy.column && this.userMultiSorting[this.orderBy.column]) {
      var col = this.userMultiSorting[this.orderBy.column].filter(function (c) {
        return c.column === column;
      })[0];
      if (col) cls += col.ascending ? this.opts.sortIcon.up : this.opts.sortIcon.down;
    }
  
    if (column == this.orderBy.column) {
      cls += this.orderBy.ascending == 1 ? this.opts.sortIcon.up : this.opts.sortIcon.down;
    }
  
    return cls;
  };