Benchmark: clear element using replaceChildren vs removeChild

HTML Preparation code:

<div id="container">
  <div>Foo</div>
  <div>Bar</div>
</div>

Script Preparation code:

const container = document.getElementById("container");

Tests:

removeChild
while (container.firstChild) { container.removeChild(container.firstChild); }
replaceChildren
container.replaceChildren()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
removeChild
replaceChildren

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_2 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.2 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 18 on iOS 18.2

View result in a separate tab

Test name	Executions per second
removeChild	306491904.0 Ops/sec
replaceChildren	28118628.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

LLMs can make mistakes. Check important info.

Let's dive into explaining the benchmark.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that tests two different approaches to clear an HTML element: `replaceChildren` and `removeChild`. The benchmark measures which approach performs better in terms of performance (measured in executions per second).

**Options compared**

Two options are being compared:

1. **replaceChildren**: This method replaces the child nodes of an element with a new set of child nodes, without removing any existing children. In this case, the test creates a container element and adds two child elements ("Foo" and "Bar") to it. The test then uses `replaceChildren` to clear the container by replacing its child nodes.
2. **removeChild**: This method removes a single child node from an element's child list. To clear the entire child list, the test repeatedly calls `removeChild` on each child node of the container.

**Pros and Cons**

Here are some pros and cons of each approach:

* **replaceChildren**:
	+ Pros: more efficient in terms of number of method calls (only one call clears the entire child list)
	+ Cons: may not be as efficient for very large child lists, as it requires creating a new set of child nodes
* **removeChild**:
	+ Pros: can be used to clear a single child node or an arbitrary subset of child nodes
	+ Cons: requires multiple method calls (one for each child node), which may be slower than `replaceChildren` in terms of performance

**Library and purpose**

There is no explicit library mentioned in the benchmark definition, but the use of `document.getElementById` and `document.replaceChildren` suggests that the test uses the native JavaScript APIs provided by browsers.

**Special JS feature or syntax**

The benchmark does not explicitly mention any special JavaScript features or syntax. However, it's worth noting that the use of `replaceChildren` is a relatively modern API introduced in ECMAScript 2015 (ES6).

**Other alternatives**

Some alternative approaches to clear an HTML element might include:

* Using a library like jQuery or another DOM manipulation library
* Using a templating engine like Handlebars or Mustache to render the content
* Using a virtual DOM library like React or Vue.js

However, in this specific benchmark, the focus is on measuring the performance difference between `replaceChildren` and `removeChild`, which makes it a relatively simple and straightforward test case.

Related benchmarks:

clear element using replaceChildren vs removeChild (version: 1)

Comparing performance of: removeChild vs replaceChildren

Created: one year ago by: Registered User

Jump to the latest result

removeChild

replaceChildren

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):