fcp.njk

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{% extends 'layout.njk' %}

{% block content %}
  <h1>FCP Test</h1>
  <p>
    <img src="/test/img/square.png?delay=500">
  </p>
  <p>Text below the image</p>

  <script type="module">
    import {getFCP} from '/dist/web-vitals.es5.min.js';

    getFCP((fcp) => {
      // Log for easier manual testing.
      console.log(fcp);

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