css/css-layout-api/fragment-data.https.html

<!DOCTYPE html>
<html class=reftest-wait>
<link rel="help" href="https://drafts.css-houdini.org/css-layout-api/#dom-layoutfragment-data">
<link rel="match" href="green-square-ref.html">
<meta name="assert" content="This test checks that passing data to a parent layout works correctly." />
<style>
.test {
  background: red;
  width: 100px;
}

@supports (display: layout(parent)) {
  .test {
    display: layout(parent);
    background: green;
  }

  .child {
    display: layout(child);
  }
}
</style>
<script src="/common/reftest-wait.js"></script>
<script src="/common/worklet-reftest.js"></script>

<div class="test">
  <div class="child"></div>
</div>

<script id="code" type="text/worklet">
const DATA = {
  str: 'hello',
  num: 42,
  obj: {str2: 'world'},
};

registerLayout('parent', class {
  async intrinsicSizes() {}
  async layout([child], edges, constraints, styleMap) {

    const childFragment = await child.layoutNextFragment();

    // Use JSON.stringify to make sure the structured cloning worked.
    if (childFragment.data !== DATA &&
        JSON.stringify(childFragment.data) === JSON.stringify(DATA)) {
      return {autoBlockSize: 100, childFragments: [childFragment]};
    }

    return {autoBlockSize: 0, childFragments: [childFragment]};
  }
});

registerLayout('child', class {
  async intrinsicSizes() {}
  async layout(children, edges, constraints, styleMap) {
    return {autoBlockSize: 10, data: DATA};
  }
});
</script>

<script>
importWorkletAndTerminateTestAfterAsyncPaint(CSS.layoutWorklet, document.getElementById('code').textContent);
</script>
</html>