Benchmark: instanceof vs type/name

Script Preparation code:

let tags = [
  'div',
  'span',
  'body',
  'a',
  'template'
];

let els = new Array(1000).fill(0).map((_, i) => document.createElement(tags[i%tags.length]));
let count = 0;

function runTest(comparator) {
  for (let i = 0; i < els.length; i++) {
	if (comparator(els[i])) {
	  count++;
    }
  }
}

Tests:

instanceof
runTest((el) => el instanceof HTMLTemplateElement);
type checking
runTest((el) => el && el.nodeType === 1 && el.nodeName.toLowerCase() === 'template');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceof
type checking

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

**What is being tested?**

MeasureThat.net is testing the performance of two different approaches to check if an HTML element is either an instance of `HTMLTemplateElement` or has specific properties (`nodeType` and `nodeName.toLowerCase()`).

The tests are comparing:

1. Checking if an element is an instance of a specific class using the `instanceof` operator.
2. Performing a type check by verifying the presence of specific properties.

**Options compared:**

There are two options being compared:

1. **Instance of**: Using the `instanceof` operator to check if an element is an instance of `HTMLTemplateElement`.
2. **Type checking**: Verifying the presence of specific properties (`nodeType` and `nodeName.toLowerCase()`) on an element.

**Pros and Cons:**

* **Instance of**:
	+ Pros: Simple, concise, and widely supported.
	+ Cons: May not cover all possible variations or edge cases (e.g., inheritance), can be slower due to the overhead of dynamic type checking.
* **Type checking**:
	+ Pros: More comprehensive, covers more edge cases, but may require more code and additional checks.
	+ Cons: May be slower due to the added complexity, less concise.

**Library/Functionality used:**

The test case uses JavaScript's built-in `HTMLTemplateElement` class, which is part of the HTML standard. The `instanceof` operator and type checking approach rely on this class being implemented correctly by browsers.

**Special JS feature/syntax:**

There are no special JavaScript features or syntaxes mentioned in the benchmark definition or test cases. The tests only use standard JavaScript syntax and built-in functions like `instanceof`.

**Other alternatives:**

Alternative approaches to check if an element is a certain type or has specific properties might include:

* Using a library like Lodash or Ramda for more complex type checks.
* Utilizing browser-specific APIs, such as Chrome's `chrome.content` API, which provides a way to access HTML elements and their properties directly.
* Implementing custom checks using regular expressions or other string manipulation techniques.

However, these alternatives are not mentioned in the provided benchmark definition.

Related benchmarks:

instanceof vs type/name (version: 0)

Comparing performance of: instanceof vs type checking

Created: 4 years ago by: Guest

Jump to the latest result

instanceof

type checking

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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