Benchmark: Object.hasOwn vs 'in' performance v2

Script Preparation code:

obj = {a: 42, b:66, c: 88}

Tests:

Object.hasOwn
Object.hasOwn(obj, 'b')
in
'b' in obj

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.hasOwn
in

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 27 days ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Linux

View result in a separate tab

Test name	Executions per second
Object.hasOwn	2324546.2 Ops/sec
in	4752044.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the benchmark and explain what's being tested, compared, and their pros and cons.

**Benchmark Overview**

The benchmark compares two ways to check if a property exists in an object: `Object.hasOwn` and the `"in"` operator (also known as the "has property" operator).

**Options Being Compared**

There are two options:

1. **`Object.hasOwn(obj, 'b')`**: This is the traditional way to check if a property exists in an object using the `Object.hasOwn()` method.
2. **"'b' in obj"`**: This uses the `"in"` operator to check if the property `'b'` exists in the object.

**Pros and Cons of Each Approach**

1. **`Object.hasOwn(obj, 'b')`**:
	* Pros: More explicit and readable way to check for property existence.
	* Cons: May be slower due to method call overhead.
2. **"'b' in obj"`:
	* Pros: Faster since it's a simple operator evaluation.
	* Cons: Less explicit and may lead to ambiguity if not used correctly.

**Library and Its Purpose**

The `Object.hasOwn()` method is a built-in JavaScript method that checks if an object has a property with the given name. It's used to avoid the error "TypeError: Cannot read own property of undefined or null" when trying to access a non-existent property.

**Special JS Feature/Syntax**

There isn't any special JS feature or syntax being tested in this benchmark, as both approaches are standard JavaScript methods and operators.

**Other Alternatives**

If you were to compare other ways to check for property existence in an object, some alternatives could be:

1. **`in` operator with `typeof`**: e.g., `'b' in obj && typeof obj['b'] !== 'undefined'`
2. **Using a library or utility function**: Some libraries, like Lodash, provide functions like `hasOwnProperty()` that can check for property existence.

**Benchmark Preparation Code**

The script preparation code creates an object `obj` with three properties: `'a'`, `'b'`, and `'c'`. The values of these properties are hardcoded as numbers (42, 66, and 88).

**Latest Benchmark Result**

The latest benchmark result shows the execution rate per second for each browser on a desktop platform. The results suggest that the `"in"` operator is faster than `Object.hasOwn()` in this specific case.

In summary, the benchmark compares two ways to check if a property exists in an object: `Object.hasOwn()` and the `"in"` operator. While both approaches have their pros and cons, the `"in"` operator appears to be slightly faster in this particular case.

Related benchmarks:

Object.hasOwn vs 'in' performance v2 (version: 0)

comparing Object.hasOwn(obj, "foo") with "foo" in obj

Comparing performance of: Object.hasOwn vs in

Created: one year ago by: Guest

Jump to the latest result

Object.hasOwn

in

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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