Benchmark: NodeIterator vs TreeWalker for Component Extraction (FIXED)

Script Preparation code:

// language=HTML
const html = `
<body>
  <h1>Doc with mix of light and shadow DOM custom elements</h1>
  <p>NOTE: we rely on Chrome's support for "declarative shadow DOM"</p>
  <x-light id="1">
    <!-- comment -->
    Lorem ipsum dolor sit amet consectetur adipisicing elit. Rerum deserunt
    dolor nesciunt ab placeat nostrum. Laborum rem quisquam ullam, officiis
    maiores fugiat fuga animi quos. Ex earum a alias magni.
  </x-light>
  <x-shadow id="2">
    <template shadowroot="open">
      <!-- comment -->
      <p>
        Lorem ipsum, dolor sit amet consectetur adipisicing elit. Ullam amet
        error delectus...
      </p>
      <slot></slot>
    </template>
    <!-- comment -->
    Impedit nesciunt excepturi perferendis quis in debitis vitae soluta
    voluptatibus praesentium repellat labore quas. Cum unde consectetur
    maiores.
  </x-shadow>
  <x-light id="3">
    Lorem ipsum dolor sit amet consectetur adipisicing elit. Rerum deserunt
    dolor nesciunt ab placeat nostrum. Laborum rem quisquam ullam, officiis
    maiores fugiat fuga animi quos. Ex earum a alias magni.
    <x-light id="3.1">
      <span>Lorem ipsum dolor sit amet</span> consectetur adipisicing elit.
      Rerum deserunt dolor nesciunt ab placeat nostrum. Laborum rem quisquam
      ullam, officiis maiores fugiat fuga animi quos. Ex earum a alias magni.
      <x-light id="3.1.1">
        Lorem ipsum dolor sit amet consectetur adipisicing elit. Rerum
        deserunt dolor nesciunt ab placeat nostrum. Laborum rem quisquam
        ullam, officiis maiores fugiat fuga animi quos. Ex earum a alias
        magni.
      </x-light>
    </x-light>
  </x-light>
  <x-shadow id="4">
    <template shadowroot="open">
      <x-shadow id="4.1">
        <template shadowroot="open">
          Lorem ipsum, dolor sit amet consectetur adipisicing elit. Ullam amet
          error delectus...
          <slot></slot>
          <x-shadow id="4.1.1">
            <template shadowroot="open">
              Lorem ipsum, dolor sit amet consectetur adipisicing elit. Ullam
              amet error delectus...
              <slot></slot>
            </template>
            Impedit nesciunt excepturi perferendis quis in debitis vitae
            soluta voluptatibus praesentium repellat labore quas. Cum unde
            consectetur maiores.
            <x-light id="4.1.1.1">
              <p>
                Lorem ipsum dolor sit amet consectetur adipisicing elit. Rerum
                deserunt dolor nesciunt ab placeat nostrum. Laborum rem
                quisquam ullam, officiis maiores fugiat fuga animi quos. Ex
                earum a alias magni.
              </p>
            </x-light>
          </x-shadow>
        </template>
        Impedit nesciunt excepturi perferendis quis in debitis vitae soluta
        voluptatibus praesentium repellat labore quas. Cum unde consectetur
        maiores.
      </x-shadow>
      <slot></slot>
    </template>
    <x-shadow id="5">
      <template shadowroot="open">
        Lorem ipsum, dolor sit amet consectetur adipisicing elit. Ullam amet
        error delectus...
        <slot></slot>
      </template>
      Impedit nesciunt excepturi perferendis quis in debitis vitae soluta
      voluptatibus praesentium repellat labore quas. Cum unde consectetur
      maiores.
    </x-shadow>
  </x-shadow>
</body>
`;
const fragment = new DOMParser().parseFromString(html, 'text/html', {
	includeShadowRoots: true
});
document.body.replaceChildren(fragment.body);

function getAllComponents(walkerFunc, root = document.body, shadowParent) {
  const components = []
  const lightParentStack = []
  let element, customElementType, customElementName, customElement
  const walker = walkerFunc(root)

  while ((element = walker.nextNode())) {
    if (
      (hasShadowRoot = !!element.shadowRoot) ||
      (customElementType = getCustomElementType(element))
    ) {
      while (
        lightParentStack.length &&
        !isAncestor(element, lightParentStack[0].element)
      ) {
        lightParentStack.shift()
      }

      lightParent = lightParentStack[0]

      if (customElementType) {
        customElementName =
          customElementType === 'built-in'
            ? element.getAttribute('is')
            : element.tagName.toLowerCase()

        customElement = {
          type: customElementType,
          name: customElementName,
          definition: customElements.get(customElementName),
        }
      } else {
        customElement = false
      }

      const component = {
        element,
        hasShadowRoot,
        customElement,
        shadowParent,
        lightParent,
        shadowChildren: [],
        lightChildren: [],
      }

      if (shadowParent) {
        shadowParent.shadowChildren.push(component)
      }

      if (lightParent) {
        lightParent.lightChildren.push(component)
      }

      components.push(component)

      // regardless of hasShadowRoot, an element can have light DOM children
      lightParentStack.unshift(component)

      if (component.hasShadowRoot) {
        components.push(
          ...getAllComponents(walkerFunc, element.shadowRoot, component)
        )
      }
    }
  }

  return components
}

function getCustomElementType(el) {
  return el.tagName.includes('-')
    ? 'autonomous'
    : el.hasAttribute('is')
    ? 'built-in'
    : null
}

function isAncestor(child, ancestor) {
  let parent = child.parentNode

  while (parent) {
    if (parent === ancestor) {
      return true
    }

    parent = parent.parentNode
  }

  return false
}

function createComponentIterator(root) {
  return document.createNodeIterator(root, NodeFilter.SHOW_ELEMENT, null)
}

function createComponentTreeWalker(root) {
  return document.createTreeWalker(root, NodeFilter.SHOW_ELEMENT, null)
}

Tests:

NodeIterator
console.log(getAllComponents(createComponentIterator))
TreeWalker
console.log(getAllComponents(createComponentTreeWalker))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
NodeIterator
TreeWalker

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

Based on the provided information, I'll attempt to answer your question.

It appears that you're asking about the performance comparison between two different methods of traversing an HTML document: `NodeIterator` and `TreeWalker`.

Given the benchmark results, it seems that the `NodeIterator` approach is faster than the `TreeWalker` approach. The `ExecutionsPerSecond` values for `NodeIterator` are significantly higher (2933.44775390625) compared to `TreeWalker` (2044.955078125).

There are several possible reasons for this performance difference:

1.  **Implementation differences**: NodeIterator and TreeWalker might be implemented differently in the Chrome browser, which could affect their performance.
2.  **Memory usage**: NodeIterator might require less memory than TreeWalker, especially when dealing with large HTML documents.
3.  **DOM traversal strategy**: The two methods might traverse the DOM differently, which could impact performance.

To further investigate this issue, I would recommend examining the Chrome browser's implementation of `NodeIterator` and `TreeWalker`, as well as optimizing the code that uses these methods to minimize any potential overhead.

If you'd like me to elaborate on any of these points or provide more suggestions for improving performance, feel free to ask!

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Linux; Android 11; GM1913) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 103 on Android

View result in a separate tab

Test name	Executions per second
NodeIterator	2933.4 Ops/sec
TreeWalker	2045.0 Ops/sec

Related benchmarks:

NodeIterator vs TreeWalker for Component Extraction (FIXED) (version: 0)

previous version used TreeWalker for both /facepalm

Comparing performance of: NodeIterator vs TreeWalker

Created: 2 years ago by: Guest

Jump to the latest result

NodeIterator

TreeWalker

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):