Benchmark: hasOwn vs hasOwnProperty vs typeof

Script Preparation code:

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

Tests:

typeof
typeof obj.d !== "undefined";
hasOwn
Object.hasOwn(obj, 'd')
hasOwnProperty
obj.hasOwnProperty( 'd' );

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
typeof
hasOwn
hasOwnProperty

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/143.0.0.0 Safari/537.36 Edg/143.0.0.0

Browser/OS: Chrome 143 on Windows

View result in a separate tab

Test name	Executions per second
typeof	152626352.0 Ops/sec
hasOwn	81012992.0 Ops/sec
hasOwnProperty	96256208.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what is being tested, compared options, pros and cons of each approach, and other considerations.

**What is being tested?**

The benchmark is testing the performance of three different methods for checking if a property exists in an object:

1. `typeof` operator
2. `Object.hasOwn()` method
3. `obj.hasOwnProperty()` method

Each method checks if the property "d" exists in the object created by the script preparation code.

**Options compared**

The benchmark is comparing the performance of these three methods:

* `typeof`: Returns a string indicating the type of the value (in this case, "undefined" for properties that don't exist).
* `Object.hasOwn()`: A method that checks if an object has a property with the specified name.
* `obj.hasOwnProperty()`: A method that checks if an object has a property with the specified name.

**Pros and cons of each approach**

1. **`typeof` operator**:
	* Pros: Lightweight, fast, and widely supported (most browsers).
	* Cons: Returns a string, which might be slower due to string processing.
2. **`Object.hasOwn()` method**:
	* Pros: Explicit, easy to read, and more intuitive than `typeof`.
	* Cons: Might be slower due to the overhead of calling a method on an object.
3. **`obj.hasOwnProperty()``` method**:
	* Pros: Lightweight, fast, and widely supported (most browsers).
	* Cons: Requires accessing the `hasOwnProperty()` property of the object, which might incur a small overhead.

**Other considerations**

* Both `Object.hasOwn()` and `obj.hasOwnProperty()` methods can be slower than `typeof` because they involve checking if an object has a certain property.
* The performance difference between these methods is likely to be negligible for most use cases.
* It's worth noting that modern JavaScript engines (V8, SpiderMonkey) are quite fast at resolving property access and will typically outperform these benchmark tests.

**Library used**

None of the test cases use any external libraries. They only rely on built-in JavaScript features and objects.

**Special JS feature or syntax**

There is no special JavaScript feature or syntax being tested in this benchmark. It's a straightforward comparison of three simple methods for checking property existence.

If you're interested in exploring other benchmarking options, here are some alternatives:

1. **Microbenchmarks on jsPerf**: A popular online platform for running microbenchmarks.
2. **Benchmarking libraries like Benchmark.js or speedtest-benchmark**: Can help with more complex benchmarking scenarios and provide detailed results.
3. **Built-in browser performance testing tools**: Many modern browsers have built-in tools for testing performance, such as Chrome's DevTools or Firefox's Performance Tool.

Related benchmarks:

hasOwn vs hasOwnProperty vs typeof (version: 0)

Object lookup performance

Comparing performance of: typeof vs hasOwn vs hasOwnProperty

Created: 3 years ago by: Guest

Jump to the latest result

typeof

hasOwn

hasOwnProperty

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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