text: /**
   * @file captions-button.js
   */
  import TextTrackButton from './text-track-button.js';
  import Component from '../../component.js';
  import CaptionSettingsMenuItem from './caption-settings-menu-item.js';
  
  /**
   * The button component for toggling and selecting captions
   *
   * @extends TextTrackButton
   */
  class CaptionsButton extends TextTrackButton {
  
    /**
     * Creates an instance of this class.
     *
     * @param {Player} player
     *        The `Player` that this class should be attached to.
     *
     * @param {Object} [options]
     *        The key/value store of player options.
     *
     * @param {Component~ReadyCallback} [ready]
     *        The function to call when this component is ready.
     */
    constructor(player, options, ready) {
      super(player, options, ready);
      this.el_.setAttribute('aria-label', 'Captions Menu');
    }
  
    /**
     * Builds the default DOM `className`.
     *
     * @return {string}
     *         The DOM `className` for this object.
     */
    buildCSSClass() {
      return `vjs-captions-button ${super.buildCSSClass()}`;
    }
  
    /**
     * Update caption menu items
     *
     * @param {EventTarget~Event} [event]
     *        The `addtrack` or `removetrack` event that caused this function to be
     *        called.
     *
     * @listens TextTrackList#addtrack
     * @listens TextTrackList#removetrack
     */
    update(event) {
      let threshold = 2;
  
      super.update();
  
      // if native, then threshold is 1 because no settings button
      if (this.player().tech_ && this.player().tech_.featuresNativeTextTracks) {
        threshold = 1;
      }
  
      if (this.items && this.items.length > threshold) {
        this.show();
      } else {
        this.hide();
      }
    }
  
    /**
     * Create caption menu items
     *
     * @return {CaptionSettingsMenuItem[]}
     *         The array of current menu items.
     */
    createItems() {
      const items = [];
  
      if (!(this.player().tech_ && this.player().tech_.featuresNativeTextTracks)) {
        items.push(new CaptionSettingsMenuItem(this.player_, {kind: this.kind_}));
      }
  
      return super.createItems(items);
    }
  
  }
  
  /**
   * `kind` of TextTrack to look for to associate it with this menu.
   *
   * @type {string}
   * @private
   */
  CaptionsButton.prototype.kind_ = 'captions';
  
  /**
   * The text that should display over the `CaptionsButton`s controls. Added for localization.
   *
   * @type {string}
   * @private
   */
  CaptionsButton.prototype.controlText_ = 'Captions';
  
  Component.registerComponent('CaptionsButton', CaptionsButton);
  export default CaptionsButton;
  