Benchmark: in vs. obj.hasOwnProperty vs prototype.hasOwnProperty.call

Script Preparation code:

var obj = { a: 1, b: 2, c: 3, d: 4, e: 5 };

Tests:

in (true)
'c' in obj;
in (false)
'q' in obj;
obj.hasOwnProperty (true)
obj.hasOwnProperty('c');
obj.hasOwnProperty (false)
obj.hasOwnProperty('q');
prototype.hasOwnProperty.call (true)
Object.prototype.hasOwnProperty.call(obj, 'c');
prototype.hasOwnProperty.call (false)
Object.prototype.hasOwnProperty.call(obj, 'q');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
in (true)
in (false)
obj.hasOwnProperty (true)
obj.hasOwnProperty (false)
prototype.hasOwnProperty.call (true)
prototype.hasOwnProperty.call (false)

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Definition**

The benchmark measures the performance of three different ways to check if an object has a specific property: `in`, `obj.hasOwnProperty()`, and `prototype.hasOwnProperty.call()`.

**Options Compared**

1. **`in`**: This operator checks if an object has a property with the given name, regardless of whether it's inherited from its prototype chain.
2. **`obj.hasOwnProperty()`**: This method checks if an object has a property with the given name, but returns `false` if the property is inherited from its prototype chain.
3. **`prototype.hasOwnProperty.call()`**: This method checks if an object has a property with the given name in its own prototype chain (i.e., not inherited from any other object's prototype).

**Pros and Cons of Each Approach**

1. **`in`**:
	* Pros: Simple, fast, and widely supported.
	* Cons: May return `true` for properties that are inherited from the prototype chain, which can be an unnecessary check.
2. **`obj.hasOwnProperty()`**:
	* Pros: More accurate than `in`, as it returns `false` for inherited properties.
	* Cons: May be slower than `in` due to the method call overhead.
3. **`prototype.hasOwnProperty.call()`**:
	* Pros: Provides more control over whether to check inherited properties, which can be useful in some scenarios.
	* Cons: May be slower than `obj.hasOwnProperty()`, and some older browsers may not support it.

**Library Usage**

In this benchmark, the `Object.prototype.hasOwnProperty.call()` method is used, which implies that the browser being tested supports the latest ECMAScript standard (ECMAScript 5). This is a common practice in modern JavaScript development.

**Special JS Features or Syntax**

There are no special JavaScript features or syntax mentioned in the benchmark definition. The test cases only use basic JavaScript syntax and semantics.

**Other Alternatives**

If you're interested in measuring performance of other JavaScript operators, such as `in` vs. `hasOwnProperty()` (using `obj`) or `in` vs. `instanceof`, MeasureThat.net might have benchmark definitions available for those scenarios as well. Additionally, you can explore other microbenchmarking libraries and frameworks, such as JsPerf or Benchmark.js, to compare performance of different JavaScript implementations.

I hope this explanation helps!

Latest run results:

Run details: (Test run date: 11 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.5993.2467 YaBrowser/23.11.0.2467 Yowser/2.5 Safari/537.36

Browser/OS: Yandex Browser 23 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
in (true)	16126449.0 Ops/sec
in (false)	16064166.0 Ops/sec
obj.hasOwnProperty (true)	14155667.0 Ops/sec
obj.hasOwnProperty (false)	13872129.0 Ops/sec
prototype.hasOwnProperty.call (true)	4741770.0 Ops/sec
prototype.hasOwnProperty.call (false)	4914296.5 Ops/sec

Related benchmarks:

in vs. obj.hasOwnProperty vs prototype.hasOwnProperty.call (version: 0)

Object lookup performance

Comparing performance of: in (true) vs in (false) vs obj.hasOwnProperty (true) vs obj.hasOwnProperty (false) vs prototype.hasOwnProperty.call (true) vs prototype.hasOwnProperty.call (false)

Created: one year ago by: Guest

Jump to the latest result

in (true)

in (false)

obj.hasOwnProperty (true)

obj.hasOwnProperty (false)

prototype.hasOwnProperty.call (true)

prototype.hasOwnProperty.call (false)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 28 days ago):