Nuxt cross-request state leak — interactive simulation

<div class="pg">
    <h1 class="pg-title">🎮 Watch two requests race for a shared cart</h1>
    <p class="pg-sub">
      This is a <b>model</b> of how a Nuxt server handles concurrent requests — plain JS
      simulating two overlapping renders, not a real Nuxt app. Pick a storage strategy, then
      fire "two requests" at once and watch what each one ends up seeing.
    </p>

<div class="banner info">
      Simulated model — walks the same interleaving a Node/Nitro server does, in plain JS. No real Nuxt server, no real HTTP request.
    </div>

<div class="panel">
      <div class="panel-label"><span class="n">1</span> Storage strategy</div>
      <div class="btn-row" style="flex-wrap:wrap; gap:14px;">
        <div class="field">
          <span class="ctl-label">Where the cart lives</span>
          <div class="seg" id="strategySeg">
            <button type="button" aria-pressed="true" data-val="module">Module-scope ref() (buggy)</button>
            <button type="button" aria-pressed="false" data-val="usestate">useState() per request (fixed)</button>
          </div>
        </div>
      </div>
      <div class="btn-row" style="margin-top:12px">
        <button class="btn primary" id="run">▶️ Fire two concurrent requests</button>
        <button class="btn ghost" id="reset">Reset</button>
      </div>
    </div>

<div class="panel">
      <div class="panel-label"><span class="n">2</span> Two users, one server</div>
      <div class="lanes">
        <div class="lane">
          <h3>User A adds <code>sku-A</code></h3>
          <div class="cart-box" id="cartA">—</div>
        </div>
        <div class="lane">
          <h3>User B adds <code>sku-B</code></h3>
          <div class="cart-box" id="cartB">—</div>
        </div>
      </div>

<div class="status" id="statusLine">
        <span class="dot info" id="dot"></span><span id="statusText">Ready — pick a strategy and fire two requests.</span>
      </div>

preview

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