cdao-pjet/app/javascript/controllers/selectize_controller.js

import ApplicationController from './application_controller'

export default class extends ApplicationController {
  connect() {
    super.connect()

    var default_opts = {
      plugins: ['restore_on_backspace', 'remove_button'],
      searchField: ['text', 'optgroup'],
      valueField: "id",
      allowEmptyOption: false,
      showEmptyOptionInDropdown: true,
      emptyOptionLabel: true,
      hideSelected: true,
      placeholder: "Please Select"
    }

    $(".default-selectize").selectize(default_opts)
  }
}