chrome/browser/resources/settings/chrome_cleanup_page/items_to_remove_list.js

// Copyright 2017 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

cr.define('settings', function() {
  /**
   * For each line in the item list, the text field will be shown in normal
   * style at front of the line. The highlightSuffix will be appended to the end
   * of line and emphasized with bold font.
   * @typedef {{
   *   text: string,
   *   highlightSuffix: ?string,
   * }}
   */
  /* #export */ let ChromeCleanupRemovalListItem;

  /**
   * The default number of items to show for files, registry keys and extensions
   * on the detailed view when user-initiated cleanups are enabled.
   */
  /* #export */ const CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW = 4;

  /**
   * @fileoverview
   * 'items-to-remove-list' represents a list of items to
   * be removed or changed to be shown on the Chrome Cleanup page.
   * TODO(crbug.com/776538): Update the strings to say that some items are only
   *                         changed and not removed.
   *
   * Example:
   *
   *    <!-- Items list initially shows |CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW|
   *         items. If there are more than
   * |CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW| items on the list, then a "show
   * more" link is shown; tapping on it expands the list. -->
   *    <items-to-remove-list
   *        title="Files and programs:"
   *        items-to-show="[[filesToShow]]">
   *    </items-to-remove-list>
   */
  Polymer({
    is: 'items-to-remove-list',

    properties: {
      title: {
        type: String,
        value: '',
      },

      /** @type {!Array<settings.ChromeCleanupRemovalListItem>} */
      itemsToShow: {
        type: Array,
        observer: 'updateVisibleState_',
      },

      /**
       * If true, all items from |itemsToShow| will be presented on the card,
       * and the "show more" link will be omitted.
       */
      expanded_: {
        type: Boolean,
        value: false,
      },

      /**
       * The first |CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW| items of |itemsToShow|
       * if the list is longer than |CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW|.
       * @private {?Array<settings.ChromeCleanupRemovalListItem>}
       */
      initialItems_: Array,

      /**
       * The remaining items to be presented that are not included in
       * |initialItems_|. Items in this list are only shown to the user if
       * |expanded_| is true.
       * @private {?Array<settings.ChromeCleanupRemovalListItem>}
       */
      remainingItems_: Array,

      /**
       * The text for the "show more" link available if not all files are
       * visible in the card.
       * @private
       */
      moreItemsLinkText_: {
        type: String,
        value: '',
      },
    },

    /** @private */
    expandList_() {
      this.expanded_ = true;
      this.moreItemsLinkText_ = '';
    },

    /**
     * Decides which elements will be visible in the card and if the "show more"
     * link will be rendered.
     *
     * 1. If size(itemsToShow) < CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW, then all
     *    items will be visible.
     * 2. Otherwise, exactly |CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW - 1| will be
     *    visible and the "show more" link will be rendered. The list presented
     * to the user will contain exactly |CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW|
     *    elements, and the last one will be the "show more" link.
     *
     * @param {!Array<settings.ChromeCleanupRemovalListItem>} itemsToShow
     */
    updateVisibleState_(itemsToShow) {
      // Start expanded if there are less than
      // |CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW| items to show.
      this.expanded_ =
          itemsToShow.length <= CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW;

      if (this.expanded_) {
        this.initialItems_ = itemsToShow;
        this.remainingItems_ = [];
        this.moreItemsLinkText_ = '';
        return;
      }

      this.initialItems_ =
          itemsToShow.slice(0, CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW - 1);
      this.remainingItems_ =
          itemsToShow.slice(CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW - 1);

      const browserProxy = settings.ChromeCleanupProxyImpl.getInstance();
      browserProxy.getMoreItemsPluralString(this.remainingItems_.length)
          .then(linkText => {
            this.moreItemsLinkText_ = linkText;
          });
    },

    /**
     * Returns the class for the <li> elements that correspond to the items
     * hidden in the default view.
     * @param {boolean} expanded
     */
    remainingItemsClass_(expanded) {
      return expanded ? 'visible-item' : 'hidden-item';
    },

    /**
     * @param {settings.ChromeCleanupRemovalListItem} item
     * @return {boolean} Whether a highlight suffix exists.
     * @private
     */
    hasHighlightSuffix_(item) {
      return item.highlightSuffix !== null;
    },
  });

  // #cr_define_end
  return {ChromeCleanupRemovalListItem, CHROME_CLEANUP_DEFAULT_ITEMS_TO_SHOW};
});