• pokemon.js

  • Modern browsers prevent mixed content. I.e., if the page is served from a safe (https) origin, they will block the content from other (non https) origins. We use this service to tunnel Pokemon API responses through a secure origin.

    var PROXY = 'https://crossorigin.me/';
  • Some times we want to measure.

    var startTime = performance.now();
    var interpolationTime = 0;
    var fetchingModelTime = 0;
  • Here is the idea. This is the template for a Pokemon. It is in charge of parsing which Pokemon is requested from the querystring of the URL, fetch that pokemon and fill the template. Once the template has been filled, we are going to mark the document as cached and send to the render-store by sending the contents to the service worker.

  • The cached mark is a simple data-* property in the document element.

    var isCached = document.documentElement.dataset.cached;
    if (isCached) {
  • If cached, log the times and we are done.

    } else {
  • If not, fetch the pokemon info, fill the character sheet, log times and cache.

      var pokemonId = getPokemonId();
  • Extract the pokemon id from the querystring.

    function getPokemonId() {
      return window.location.search.split('=')[1];
  • Fetch pokemon’s info as JSON.

    function getPokemon(id) {
      var fetchingModelStart = performance.now();
      var url = PROXY + 'http://pokeapi.co/api/v1/pokemon/' + id + '/?_b=' + Date.now();
      return fetch(url).then(function(response) {
        fetchingModelTime = performance.now() - fetchingModelStart;
        return response.json();
  • Take the contents of the body as template and interpolate with the pokemon info.

    function fillCharSheet(pokemon) {
      var element = document.querySelector('body');
      element.innerHTML = interpolateTemplate(element.innerHTML, pokemon);
  • Specifically for the cookbook site :(

      document.querySelector('img').onload = function() {
        if (window.parent === window) {
        window.parent.document.body.dispatchEvent(new CustomEvent('iframeresize'));
  • Log times for interpolation, fetching and total loading times.

    function logTime() {
      var loadingTimeLabel = document.querySelector('#loading-time-label');
      var interpolationTimeLabel =
      var fetchingModelTimeLabel = document.querySelector('#fetching-time-label');
      loadingTimeLabel.textContent = (performance.now() - startTime) + ' ms';
      interpolationTimeLabel.textContent = interpolationTime + ' ms';
      fetchingModelTimeLabel.textContent = fetchingModelTime + ' ms';
  • Mark the documents as cached, then gets all the HTML content and send to the service worker using a PUT request into ./render-store/ URL. You could be wondering we need to send the URL for the cached content but this info is implicitly added as the referrer property of the request.

    function cache() {
      document.documentElement.dataset.cached = true;
      var data = document.documentElement.outerHTML;
      fetch('./render-store/', { method: 'PUT', body: data }).then(function() {
        console.log('Page cached');
  • Look for {{key}} fragments inside the template and replace them with the values of pokemon[key].

    function interpolateTemplate(template, pokemon) {
      var interpolationStart = performance.now();
      var result = template.replace(/{{(\w+)}}/g, function(match, field) {
        return pokemon[field];
      interpolationTime = performance.now() - interpolationStart;
      return result;

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