Benchmark: Instanceof vs property access

Script Preparation code:

elem  = document.createElement('div');

Tests:

Instanceof
elem instanceof HTMLElement
property access
elem.nodeType === Node.ELEMENT_NODE

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Instanceof
property access

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; rv:120.0) Gecko/20100101 Firefox/120.0

Browser/OS: Firefox 120 on Linux

View result in a separate tab

Test name	Executions per second
Instanceof	14132819.0 Ops/sec
property access	1766175104.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**What is tested on the provided JSON?**

The provided JSON represents a JavaScript microbenchmark test case, specifically comparing two approaches: `instanceof` and property access. The test aims to measure the performance difference between these two methods when checking if an object is of type `HTMLElement`.

**Options compared:**

1. **`instanceof`**: This method checks if an object is an instance of a specific constructor. In this case, it's used to check if `elem` is an instance of `HTMLElement`.
2. **Property access**: This approach uses the `nodeType` property to check if `elem` is an element node.

**Pros and cons of each approach:**

*   **`instanceof`**:
    *   Pros:
        *   More explicit and readable code
        *   Can be more efficient for certain types of objects (e.g., when the object's constructor has a unique signature)
    *   Cons:
        *   May incur additional overhead due to the lookup in the `Prototype` chain
        *   Might not work as expected if the object's prototype is changed or inherited from multiple prototypes
*   **Property access**:
    *   Pros:
        *   Typically faster and more lightweight than `instanceof`
        *   Works well for checking basic node types (e.g., element, text, comment)
    *   Cons:
        *   Less readable code, as the property name is not immediately obvious
        *   Might require additional checks to ensure the correct property exists

**Library and purpose:**

There is no specific library mentioned in the JSON. The test relies on built-in JavaScript functionality.

**Special JS feature or syntax:**

There are no special features or syntaxes mentioned in this benchmark. It's a straightforward test case that uses standard JavaScript constructs.

**Alternative approaches:**

Other alternatives to `instanceof` and property access could include:

*   Using the `isElement` function from a library like jQuery (although not explicitly used here, it suggests an alternative approach)
*   Employing a custom implementation using bitwise operations or other performance-critical methods
*   Leveraging compiler optimizations or Just-In-Time (JIT) compilation to reduce overhead

For this specific benchmark, the choice between `instanceof` and property access depends on the desired balance between readability, maintainability, and performance.

Related benchmarks:

Instanceof vs property access (version: 0)

Comparing performance of: Instanceof vs property access

Created: 2 years ago by: Guest

Jump to the latest result

Instanceof

property access

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):