Issue #3278109 by matsbla: Tokenize pasted strings

(function ($, Drupal, drupalSettings) {

  'use strict';

  /**

   * Customize tokenizer.

   *

   * @param {object} $params

   *   Tokenizer parameters

   * @param {object} $e

   *   Tokenizer element

   * @param {function} $callback

   *   Tokenizer callback

   */

  const tokenizer = function(params, e, callback) {

    var separators = e.options.tokenSeparators || [];

    var term = params.term;

    var i = 0;

    var createTag = this.createTag || function (params) {

      return {

        id: params.term,

        text: params.term

      };

    };

    if (term.length && separators.length && $.inArray(term.slice(-1), separators) === -1) {

      term = term + separators[0];

    }

    while (i < term.length) {

      var termChar = term[i];

      if ($.inArray(termChar, separators) === -1) {

        i++;

        continue;

      }

      var part = term.substr(0, i);

      var partParams = $.extend({}, params, {

        term: part

      });

      var data = createTag(partParams);

      if (data == null) {

        i++;

        continue;

      }

      callback(data);

      // Reset the term to not include the tokenized portion

      term = term.substr(i + 1) || '';

      i = 0;

    }

    return {

      term: term

    };

  }

  Drupal.behaviors.select2widget = {

    attach: function (context) {

      // Additional code to make removing/creating elements correctly works.

          width: 'style',

          tags: autocreate,

          tokenSeparators: [','],

          tokenizer,

          containerCssClass: (drupalSettings.preloaded_entries && drupalSettings.preloaded_entries[field_name])

            ? 'preloaded'

            : '',

          multiple: multiple,

          tags: autocreate,

          tokenSeparators: [','],

          tokenizer,

          templateResult: flagsIcons,

          templateSelection: flagsIcons

        });