Benchmark: instanceof vs namespaceURI

Script Preparation code:

var svg = document.createElementNS("http://www.w3.org/2000/svg", "svg")

Tests:

instanceof
svg instanceof SVGElement
namespaceURI
svg.namespaceURI === "http://www.w3.org/2000/svg"
body.namespaceURI
svg.namespaceURI === document.body.namespaceURI

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceof
namespaceURI
body.namespaceURI

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser/OS: Chrome 110 on Linux

View result in a separate tab

Test name	Executions per second
instanceof	7079618.5 Ops/sec
namespaceURI	20432756.0 Ops/sec
body.namespaceURI	4942736.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and its results, explaining what's being tested, the options compared, their pros and cons, and other considerations.

**Benchmark Description**

The benchmark is designed to compare the performance of three different approaches for checking the namespace URI of an SVG element in JavaScript:

1. `svg instanceof SVGElement`
2. `svg.namespaceURI === "http://www.w3.org/2000/svg"`
3. `svg.namespaceURI === document.body.namespaceURI`

**Options Compared**

The options compared are:

A) Using the `instanceof` operator to check if an object is an instance of a specific constructor (`SVGElement` in this case).

B) Directly comparing the namespace URI of an SVG element using a string literal ("http://www.w3.org/2000/svg").

C) Comparing the namespace URI of an SVG element with the namespace URI of the `body` element.

**Pros and Cons**

A) Using `instanceof`: This approach is concise and expressive, but it may not be as efficient as other methods, especially for large datasets. The `instanceof` operator checks if an object is a constructor's prototype chain, which can lead to slower performance.

B) Direct comparison: This approach is simple and straightforward, but it has limitations. If the namespace URI changes, this comparison will fail. Additionally, comparing strings using the `===` operator involves additional overhead due to string normalization.

C) Comparison with `body.namespaceURI`: This approach has similar pros and cons as B), but it also introduces an extra lookup operation by accessing the `namespaceURI` property of `document.body`.

**Library Usage**

There is no explicit library usage mentioned in the benchmark definition. However, it's worth noting that some browsers (like Chrome) may use internal APIs or optimizations to compare namespace URIs.

**Special JS Features/Syntax**

None are explicitly mentioned. However, some features like `const` and `let` declarations, arrow functions, and template literals are not used in the benchmark code. This is a good sign, as it suggests that the test cases are focused on core JavaScript functionality rather than modern syntax or features.

**Alternative Approaches**

Other approaches to check the namespace URI of an SVG element could include:

* Using `window(namespaceURI)` (not shown in the benchmark code)
* Implementing a custom comparison function using the `String.prototype.normalize()` method
* Utilizing browser-specific APIs, like `DOMTokenList` or `SVGElement::namespaceURI` property

Keep in mind that these alternatives might have different performance characteristics, limitations, and compatibility across different browsers.

Overall, the benchmark provides valuable insights into the relative performance of three distinct approaches for checking namespace URIs. By comparing these methods, users can choose the most efficient solution for their specific use case.

Related benchmarks:

instanceof vs namespaceURI (version: 0)

Comparing performance of: instanceof vs namespaceURI vs body.namespaceURI

Created: one year ago by: Registered User

Jump to the latest result

instanceof

namespaceURI

body.namespaceURI

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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