Benchmark: instanceof vs hasOwnProperty

Script Preparation code:

var obj = {a: 1}

Tests:

instanceOf
obj instanceof Object
hasOwnProperty
obj.hasOwnProperty('a')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instanceOf
hasOwnProperty

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmark and its results.

The provided JSON represents a JavaScript microbenchmark called "instanceof vs hasOwnProperty". This benchmark tests two different methods for checking if an object has a specific property: `hasOwnProperty` and `instanceof`.

**What is tested?**

In this benchmark, we're comparing the performance of two different approaches:

1. **`hasOwnProperty`**: This method checks if the object has a property with the given name. It returns `true` if the property exists, and `false` otherwise.
2. **`instanceof`**: This method checks if an object is an instance of a particular constructor function. In this case, we're testing `instanceof Object`, which means checking if the object is an instance of the `Object` class.

**Options compared**

The benchmark compares the performance of these two approaches:

* `hasOwnProperty`: Checks for the existence of a property with the given name.
* `instanceof`: Checks if the object is an instance of a particular constructor function.

**Pros and Cons**

Here are some pros and cons of each approach:

* **`hasOwnProperty`**:
	+ Pros: Simple, efficient, and widely supported.
	+ Cons: May not work as expected with nested objects or arrays, and may be slower for large datasets.
* **`instanceof`**:
	+ Pros: Can handle nested objects and arrays, and is often faster than `hasOwnProperty`.
	+ Cons: May require additional dependencies (e.g., polyfills), and can be slower due to the overhead of type checking.

**Library usage**

In this benchmark, no libraries are explicitly mentioned. However, it's worth noting that some JavaScript engines may have internal optimizations or features that could affect performance.

**Special JS feature or syntax**

This benchmark doesn't use any special JavaScript features or syntax beyond what's commonly found in modern browsers. The only notable aspect is the use of `instanceof` and `hasOwnProperty`, which are built-in methods for checking object properties.

**Other alternatives**

If you were to implement this benchmark, some alternative approaches could include:

* Using a library like Lodash (specifically, its `_.has()` method) to compare performance with native methods.
* Implementing a custom search algorithm using techniques like hashing or indexing.
* Using a different property access method, such as `in` or ` bracket notation`.

Keep in mind that the choice of approach depends on the specific requirements and constraints of your project.

**Benchmark preparation code**

The provided JavaScript code creates an object `obj` with a single property `a`, which is used as the test subject for both benchmarks.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:120.0) Gecko/20100101 Firefox/120.0

Browser/OS: Firefox 120 on Windows

View result in a separate tab

Test name	Executions per second
instanceOf	126827472.0 Ops/sec
hasOwnProperty	810699200.0 Ops/sec

Related benchmarks:

instanceof vs hasOwnProperty (version: 0)

Comparing performance of: instanceOf vs hasOwnProperty

Created: 5 years ago by: Guest

Jump to the latest result

instanceOf

hasOwnProperty

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):