ttfb.njk

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 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.
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 See the License for the specific language governing permissions and
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-->
{% extends 'layout.njk' %}

{% block content %}
  <h1>TTFB Test</h1>
  <p>
    <img src="/test/img/square.png{% if imgDelay %}?delay={{imgDelay}}{% endif %}">
  </p>

  <p>Text below the image</p>

  <p><a id="navigate-away" href="https://example.com">Navigate away</a></p>

  <script>
    // Set the blocking values based on query params if present.
    const params = new URLSearchParams(location.search);

    if (params.has('responseStart')) {
      const navEntry = performance.getEntriesByType('navigation')[0];
      Object.defineProperty(navEntry, 'responseStart', {
        value: Number(params.get('responseStart')),
      });
    }
  </script>

  <script type="module">
    import {onTTFB} from '{{ modulePath }}';

    function jsonifyEntry(entry) {
      const newObj = {};
      for (const k in entry) {
        if (typeof entry[k] !== 'function') {
          newObj[k] = entry[k];
        }
      }
      return newObj;
    }

    (async function() {
      {% if awaitLoad %}
        await new Promise((resolve) => addEventListener('load', resolve));
      {% endif %}

      onTTFB((ttfb) => {
        // Log for easier manual testing.
        console.log(ttfb);

        // The stubbed `activationStart` is lost when stringified, so we convert first.
        ttfb.entries = ttfb.entries.map(jsonifyEntry);
        if (ttfb.attribution && ttfb.attribution.navigationEntry) {
          ttfb.attribution.navigationEntry = jsonifyEntry(ttfb.attribution.navigationEntry);
        }

        // Test sending the metric to an analytics endpoint.
        navigator.sendBeacon(`/collect`, JSON.stringify(ttfb));
      }, {reportAllChanges: self.__reportAllChanges});
    }());
  </script>
{% endblock %}