text: /**
  * Copyright 2012-2019, Plotly, Inc.
  * All rights reserved.
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
  */
  
  'use strict';
  
  /**
   * Push array with unique items
   *
   * Ignores falsy items, except 0 so we can use it to construct arrays of indices.
   *
   * @param {array} array
   *  array to be filled
   * @param {any} item
   *  item to be or not to be inserted
   * @return {array}
   *  ref to array (now possibly containing one more item)
   *
   */
  module.exports = function pushUnique(array, item) {
      if(item instanceof RegExp) {
          var itemStr = item.toString();
          for(var i = 0; i < array.length; i++) {
              if(array[i] instanceof RegExp && array[i].toString() === itemStr) {
                  return array;
              }
          }
          array.push(item);
      }
      else if((item || item === 0) && array.indexOf(item) === -1) array.push(item);
  
      return array;
  };
  