Benchmark: hasOwnProperty vs direct access (bool) vs in 2

Script Preparation code:

var x = { a: 1, b: 2, c: 3, d: 4, e: 5, f: 6, g: 7, h: 8, i: 9}

Tests:

hasOwnProperty
x.hasOwnProperty("a")
direct access (bool)
x["a"]
in
"a" in x
object
Object.prototype.hasOwnProperty.call(x, 'a')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
hasOwnProperty
direct access (bool)
in
object

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) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36

Browser/OS: Chrome 135 on Linux

View result in a separate tab

direct access (bool)

204.1M/s

201.4M/s

hasOwnProperty

97.5M/s

object

83.0M/s

View exact numbers

Test name	Executions per second
✓ direct access (bool)	204,143,856 Ops/sec
in	201,358,592 Ops/sec
hasOwnProperty	97,512,392 Ops/sec
object	82,969,592 Ops/sec

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

LLMs can make mistakes. Check important info.

The provided JSON represents a JavaScript benchmark test case created using MeasureThat.net. The test compares the performance of three different approaches to access a property in an object: `.hasOwnProperty`, direct array indexing, and the `in` operator.

Let's break down each approach:

1. **hasOwnProperty**: This method checks if the object has a property with the given name. It returns a boolean value indicating whether the property exists or not.
2. **Direct access (bool)**: This approach accesses the property directly using square brackets (`x['a']`). If the property exists, it returns the value; otherwise, it returns `undefined`.
3. **in**: This operator checks if an object has a property with a given name. It returns a boolean value indicating whether the property exists or not.

**Pros and Cons of each approach:**

1. **hasOwnProperty**:
	* Pros: Efficient in terms of CPU cycles, as it only performs a single lookup.
	* Cons: May be slower than direct array indexing for large objects due to the extra overhead of checking if the object has the property.
2. **Direct access (bool)**:
	* Pros: Often faster than `hasOwnProperty` because it doesn't require an additional lookup.
	* Cons: May cause errors if the index is out of bounds or not a valid string.
3. **in**:
	* Pros: Generally faster and more readable than `hasOwnProperty`.
	* Cons: May be slower than direct array indexing due to the extra overhead of checking if the object has the property.

**Library usage:**

None of the approaches require any external libraries.

**Special JavaScript features or syntax:**

There are no special features or syntax used in this benchmark test case.

Now, let's discuss other alternatives that could be tested:

1. **Object.prototype.hasOwnProperty.call()**: This is another way to check if an object has a property using `hasOwnProperty`. While it may seem like the same thing as `hasOwnProperty`, there are some differences in behavior due to the extra overhead of calling `call()` on the prototype.
2. ** bracket notation** (`x['a']`): Instead of direct array indexing, one could use bracket notation for better readability and maintainability. However, this approach would likely be slower than direct array indexing.

These alternatives could provide additional insights into the performance characteristics of each approach, but they may not significantly affect the overall results due to the small scope of this benchmark test case.

In summary, `hasOwnProperty`, direct access (bool), and `in` are the three primary approaches being tested in this benchmark. While there are some pros and cons associated with each approach, `in` is generally considered the most readable and efficient method.

hasOwnProperty vs direct access (bool) vs in 2 (version: 0) Benchmark.js

Comparing performance of: `hasOwnProperty vs direct access (bool) vs in vs object`

Created: 2 years ago by: Registered User

Go to the latest result

hasOwnProperty

direct access (bool)

in

object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

hasOwnProperty vs direct access (bool) vs in 2 (version: 0) Benchmark.js

Comparing performance of: hasOwnProperty vs direct access (bool) vs in vs object

Created: 2 years ago by: Registered User

Go to the latest result

hasOwnProperty

direct access (bool)

in

object

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `hasOwnProperty vs direct access (bool) vs in vs object`