Benchmark: Object.prototype.hasOwnProperty vs obj.hasOwnProperty

Script Preparation code:

window.obj = { a: 2 }

Tests:

Object.prototype.hasOwnProperty
Object.prototype.hasOwnProperty.call(obj, 'a');
obj.hasOwnProperty
obj.hasOwnProperty('a');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.prototype.hasOwnProperty
obj.hasOwnProperty

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/95.0.4638.69 Safari/537.36

Browser/OS: Chrome 95 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Object.prototype.hasOwnProperty	4008182.2 Ops/sec
obj.hasOwnProperty	8062589.5 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**What is being tested?**

The provided benchmark compares two approaches to check if an object has a certain property: `Object.prototype.hasOwnProperty.call(obj, 'a')` and `obj.hasOwnProperty('a')`. Both methods aim to determine whether the `obj` object has a property named `'a'`.

**Options compared:**

1. **`Object.prototype.hasOwnProperty.call(obj, 'a')`**: This method uses the `hasOwnProperty()` method on the `Object.prototype`, which is a built-in JavaScript method that checks if an object has a certain property. The `call()` method is used to specify the context (in this case, `obj`) for the `hasOwnProperty()` call.
2. **`obj.hasOwnProperty('a')`**: This method uses the `hasOwnProperty()` method on the `obj` itself, which means it's checking if `obj` has a property named `'a'`.

**Pros and Cons:**

* **`Object.prototype.hasOwnProperty.call(obj, 'a')`**:
	+ Pros:
		- This approach ensures that `hasOwnProperty()` is called on the correct object (either `obj` or `Object.prototype`, depending on the context).
	+ Cons:
		- It's slower because it involves a call to `call()`.
* **`obj.hasOwnProperty('a')`**:
	+ Pros:
		- This approach is faster, as it only checks if `obj` has a property named `'a'`.
	+ Cons:
		- The behavior might be different depending on the context (e.g., in some cases, it will call `hasOwnProperty()` on `Object.prototype`, which can lead to unexpected results).

**Library and purpose:**

In this benchmark, there is no explicit library used. However, `Object.prototype.hasOwnProperty` is a built-in JavaScript method that's commonly used for object property checks.

**Special JS feature or syntax:**

There are no special features or syntax mentioned in the provided code snippets.

**Other alternatives:**

Alternative approaches to check if an object has a certain property include:

* Using the bracket notation (`obj['a']`): This approach is faster but might be less readable and more error-prone, as it's vulnerable to property name mangling.
* Using `in` operator: This approach checks if a property exists in the object using the `in` operator (e.g., `"a" in obj`). While this approach can be concise, it's generally slower than `hasOwnProperty()`.

Keep in mind that the performance difference between these approaches might be negligible for most use cases. However, when writing microbenchmarks, precision and accuracy are crucial to get a fair comparison of different methods.

Related benchmarks:

Object.prototype.hasOwnProperty vs obj.hasOwnProperty (version: 0)

Comparing performance of: Object.prototype.hasOwnProperty vs obj.hasOwnProperty

Created: 3 years ago by: Guest

Jump to the latest result

Object.prototype.hasOwnProperty

obj.hasOwnProperty

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):