magic.js

/**
 * Copyright 2020 Google LLC
 *
 * 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 messages from '../:messages.json?module';
import {join} from './lib/url.js';

/**
 * @fileoverview Magic helpers for development. These should only be used as tagged templates and,
 * in production, are replaced with raw strings.
 *
 * These have matching externs in build/transpile/externs.js, for our Closure code.
 */

 /**
  * Returns the English development string for Santa Tracker.
  *
  * @param {string} id of message
  * @return {string|?} resulting text of message
  */
export function _msg(id) {
  const data = messages[id.toString()];
  return data && (data.raw || data.message) || '?';
}

/**
 * Returns the given path under Santa Tracker's static serving path.
 *
 * @param {string} path to join to static
 * @return {string} resolved path
 */
export function _static(path) {
  // FIXME: we're hoping that a compile can do something with `import.meta.url`.
  return join(import.meta.url, '..', path.toString());
}


/**
 * Upgrades all elements with `msgid="..."` as a single startup task. This is compiled for release
 * and we don't expect to see any inside Shadow DOM (should use `_msg`).
 *
 * This makes this file have side effects. This is probably fine.
 */
(function() {
  function upgrade(el) {
    if (el.localName === 'i18n-msg') {
      if (el.textContent !== 'PLACEHOLDER_i18n') {
        console.warn('i18n-msg with bad text', el.textContent)
      }
    } else if (el.childNodes.length) {
      console.warn('[msgid] with childNodes', el);
    }

    if (document.head.contains(el)) {
      // Don't do anything. It's not really worth testing anything here, just for release.
      return;
    }

    el.innerHTML = _msg(el.getAttribute('msgid'));
  }

  Array.from(document.body.querySelectorAll('[msgid]')).map(upgrade);
}());