polygerrit-ui/app/elements/plugins/gr-plugin-host/gr-plugin-host.js

/**
 * @license
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import '../../shared/gr-js-api-interface/gr-js-api-interface.js';
import {GestureEventListeners} from '@polymer/polymer/lib/mixins/gesture-event-listeners.js';
import {LegacyElementMixin} from '@polymer/polymer/lib/legacy/legacy-element-mixin.js';
import {PolymerElement} from '@polymer/polymer/polymer-element.js';
import {pluginLoader} from '../../shared/gr-js-api-interface/gr-plugin-loader.js';

/** @extends PolymerElement */
class GrPluginHost extends GestureEventListeners(
    LegacyElementMixin(
        PolymerElement)) {
  static get is() { return 'gr-plugin-host'; }

  static get properties() {
    return {
      config: {
        type: Object,
        observer: '_configChanged',
      },
    };
  }

  _configChanged(config) {
    const plugins = config.plugin;
    const htmlPlugins = (plugins && plugins.html_resource_paths || []);
    const jsPlugins = this._handleMigrations(
        plugins && plugins.js_resource_paths || [], htmlPlugins
    );
    const shouldLoadTheme = config.default_theme &&
          !pluginLoader.isPluginPreloaded('preloaded:gerrit-theme');
    const themeToLoad =
          shouldLoadTheme ? [config.default_theme] : [];

    // Theme should be loaded first if has one to have better UX
    const pluginsPending =
        themeToLoad.concat(jsPlugins, htmlPlugins);

    const pluginOpts = {};

    if (shouldLoadTheme) {
      // Theme needs to be loaded synchronous.
      pluginOpts[config.default_theme] = {sync: true};
    }

    pluginLoader.loadPlugins(pluginsPending, pluginOpts);
  }

  /**
   * Omit .js plugins that have .html counterparts.
   * For example, if plugin provides foo.js and foo.html, skip foo.js.
   */
  _handleMigrations(jsPlugins, htmlPlugins) {
    return jsPlugins.filter(url => {
      const counterpart = url.replace(/\.js$/, '.html');
      return !htmlPlugins.includes(counterpart);
    });
  }
}

customElements.define(GrPluginHost.is, GrPluginHost);