Benchmark: nodeType vs instanceof 2

Script Preparation code:

var xs = [];
var n = 0;

for (let i = 0; i < 1000; ++i) {
  xs[i] = (Math.random() > .5) ? document.createElement(`a`) : document.createTextNode(``);
};

Tests:

nodeType
n += (xs[(Math.random() * 1000)|0].nodeType === Node.ELEMENT_NODE)|0;
instanceof
n += ((xs[(Math.random() * 1000)|0]) instanceof HTMLElement)|0;
nodeType literal
n += (xs[(Math.random() * 1000)|0].hasOwnProperty('nodeType'))|0;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
nodeType
instanceof
nodeType literal

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:138.0) Gecko/20100101 Firefox/138.0

Browser/OS: Firefox 138 on Linux

View result in a separate tab

Test name	Executions per second
nodeType	74971784.0 Ops/sec
instanceof	40754232.0 Ops/sec
nodeType literal	101104152.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, compared, and the pros/cons of each approach.

**Benchmark Overview**

The benchmark measures the performance difference between three ways to check if an element is an instance of the `HTMLElement` type in JavaScript. The test case uses a large array (`xs`) containing a mix of HTML elements (e.g., anchor tags) and text nodes, which are randomly assigned to be either real or non-existent HTML elements.

**Options Compared**

1. **nodeType literal**: This approach checks if the element has a `nodeType` property that equals 1, which is the value for an HTML element.
2. **nodeType**: This approach directly accesses the `nodeType` property of the element without checking if it exists.
3. **instanceof HTMLElement**: This approach uses the `instanceof` operator to check if the element is an instance of the `HTMLElement` class.

**Pros and Cons**

1. **nodeType literal**:
	* Pros: Simple and efficient, as it avoids potential null pointer exceptions or type errors.
	* Cons: May not work correctly for non-standard elements (e.g., canvas) that have a different `nodeType`.
2. **nodeType**:
	* Pros: Fast and straightforward, but may lead to performance issues if the element's `nodeType` property is accessed frequently.
	* Cons: Potential null pointer exceptions or type errors if the element doesn't have this property.
3. **instanceof HTMLElement**:
	* Pros: Robust and reliable, as it checks for a specific class hierarchy.
	* Cons: May be slower than direct property access due to the type checking overhead.

**Library/Feature**

None of the options use a library or feature that's not part of the standard JavaScript language. However, the `HTMLElement` class is a built-in class in modern browsers, and its usage may require additional features like `prototype` chain lookup (not explicitly mentioned in the benchmark).

**Special JS Feature/Syntax**

There are no special JS features or syntax used in this benchmark that would make it unique or non-standard. The test case uses standard JavaScript variables, loops, and conditional statements.

**Other Alternatives**

If you're looking for alternative approaches to check if an element is an instance of a specific class in JavaScript, you could consider:

1. **class-based approach**: Use the `instanceof` operator with a custom class constructor that checks for the desired properties or behavior.
2. **function-based approach**: Create a function that takes an object as an argument and returns true if it matches the desired criteria.
3. **enum-based approach**: Use enums to define a set of values that can be checked against, which can provide a more explicit and type-safe way of checking instances.

These alternatives might be useful in specific scenarios where the `instanceof` operator or direct property access isn't sufficient or efficient enough.

Related benchmarks:

nodeType vs instanceof 2 (version: 0)

Comparing performance of: nodeType vs instanceof vs nodeType literal

Created: 4 years ago by: Guest

Jump to the latest result

nodeType

instanceof

nodeType literal

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 6 months ago):