lbry-desktop/ui/component/viewers/videoViewer/internal/plugins/videojs-hls-quality-selector/ConcreteButton.js

import videojs from 'video.js';

const VideoJsButtonClass = videojs.getComponent('MenuButton');
const VideoJsMenuClass = videojs.getComponent('Menu');
const VideoJsComponent = videojs.getComponent('Component');
const Dom = videojs.dom;

/**
 * Convert string to title case.
 *
 * @param {string} string - the string to convert
 * @return {string} the returned titlecase string
 */
function toTitleCase(string) {
  if (typeof string !== 'string') {
    return string;
  }

  return string.charAt(0).toUpperCase() + string.slice(1);
}

/**
 * Extend vjs button class for quality button.
 */
export default class ConcreteButton extends VideoJsButtonClass {

  /**
   * Button constructor.
   *
   * @param {Player} player - videojs player instance
   */
  constructor(player) {
    super(player, {
      title: player.localize('Quality'),
      name: 'QualityButton'
    });
  }

  /**
   * Creates button items.
   *
   * @return {Array} - Button items
   */
  createItems() {
    return [];
  }

  /**
   * Create the menu and add all items to it.
   *
   * @return {Menu}
   *         The constructed menu
   */
  createMenu() {
    const menu = new VideoJsMenuClass(this.player_, {menuButton: this});

    this.hideThreshold_ = 0;

    // Add a title list item to the top
    if (this.options_.title) {
      const titleEl = Dom.createEl('li', {
        className: 'vjs-menu-title',
        innerHTML: toTitleCase(this.options_.title),
        tabIndex: -1
      });
      const titleComponent = new VideoJsComponent(this.player_, {el: titleEl});

      this.hideThreshold_ += 1;

      menu.addItem(titleComponent);
    }

    this.items = this.createItems();

    if (this.items) {
      // Add menu items to the menu
      for (let i = 0; i < this.items.length; i++) {
        menu.addItem(this.items[i]);
      }
    }

    return menu;

  }
}