<h2>A diagram</h2>

<pre class="mermaid"><code>graph TD;
    A--&gt;B;
    A--&gt;C;
    B--&gt;D;
    C--&gt;D;</code></pre>

<hr>

<h2>Another diagram</h2>

<pre><code class="language-mermaid">gantt
    title My Product Roadmap
    dateFormat  YYYY-MM-DD
    section Cool Feature
    A task           :a1, 2022-02-25, 30d
    Another task     :after a1, 20d
    section Rad Feature
    Task in sequence :2022-03-04, 12d
    Task, No. 2      :24d
</code></pre>
import mermaid from "https://cdn.skypack.dev/[email protected]";

// select <pre class="mermaid"> _and_ <pre><code class="language-mermaid">
document.querySelectorAll("pre.mermaid, pre>code.language-mermaid").forEach($el => {
  // if the second selector got a hit, reference the parent <pre>
  if ($el.tagName === "CODE")
    $el = $el.parentElement
  // put the Mermaid contents in the expected <div class="mermaid">
  // plus keep the original contents in a nice <details>
  $el.outerHTML = `
    <div class="mermaid">${$el.textContent}</div>
    <details>
      <summary>Diagram source</summary>
      <pre>${$el.textContent}</pre>
    </details>
  `
})


// initialize Mermaid to [1] log errors, [2] have loose security for first-party
// authored diagrams, and [3] respect a preferred dark color scheme
mermaid.initialize({
  logLevel: "error", // [1]
  securityLevel: "loose", // [2]
  theme: (window.matchMedia && window.matchMedia("(prefers-color-scheme: dark)").matches) ?
    "dark" :
    "default" // [3]
})

External CSS

  1. https://unpkg.com/[email protected]/simple.min.css

External JavaScript

This Pen doesn't use any external JavaScript resources.