Benchmark: hasown vs undefined fixed

Tests:

hasown existing
const data = { foo: 3, }; let res = Object.hasOwn(data, "foo");
hasown missing
const data = { foo: 3, }; let res = Object.hasOwn(data, "bar");
undefined existing
const data = { foo: 3, }; let res = data.foo === undefined;
undefined missing
const data = { foo: 3, }; let res = data.bar === undefined;
destructure existing
const data = { foo: 3, }; let { foo } = data; let res = foo === undefined;
destructure missing
const data = { foo: 3, }; let { bar } = data; let res = bar === undefined;

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
hasown existing
hasown missing
undefined existing
undefined missing
destructure existing
destructure missing

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of what is tested on the provided JSON that represents the benchmark.

**Benchmark Test**

The test measures the speed of different approaches to check if a property exists in an object or not, specifically using the `Object.hasOwn()` method and its alternatives. The test consists of four main cases:

1. **hasown existing**: Tests whether the `Object.hasOwn()` method is faster when checking for an existing property.
2. **hasown missing**: Tests whether the `Object.hasOwn()` method is faster when checking for a non-existent property.
3. **undefined existing**: Tests whether the `=== undefined` comparison is faster when checking if a property exists in the object itself (i.e., not through the `hasOwn()` method).
4. **undefined missing**: Tests whether the `=== undefined` comparison is faster when checking if a property does not exist in the object.

**Comparison Options**

The test compares the performance of two main approaches:

1. **`Object.hasOwn()` method**: This is the traditional way to check if a property exists in an object.
2. **`=== undefined` comparison**: This approach checks directly if the property value is `undefined`, which can be faster than using the `hasOwn()` method.

**Pros and Cons**

**1. `Object.hasOwn()` method:**
	* Pros:
		+ More explicit and readable code
		+ Works in older browsers that don't support the `=== undefined` comparison
	* Cons:
		+ Can be slower due to the overhead of the `hasOwn()` method call
		+ May require more memory access

**2. `=== undefined` comparison:**
	* Pros:
		+ Faster execution time, as it only compares the value with `undefined`
		+ More concise code
	* Cons:
		+ Less explicit and readable code
		+ May not work in older browsers that don't support this syntax

**Other Considerations**

When deciding between these two approaches, consider the trade-off between readability and performance. If you prioritize brevity and speed, the `=== undefined` comparison might be a better choice. However, if you prefer more explicit code, the `Object.hasOwn()` method is a safer bet.

In terms of other alternatives, there's another approach that's gaining popularity: **`in` operator**. The `in` operator checks if a property exists in an object, but it has some differences from `hasOwn()`. For example, `in` includes inherited properties, while `hasOwn()` only considers own properties.

```javascript
const data = { foo: 3 };
console.log('foo' in data); // true
console.log(Object.hasOwn(data, 'foo')); // true
```

In the context of this benchmark, using the `in` operator would likely produce different results than using `Object.hasOwn()` or the `=== undefined` comparison.

Overall, understanding these differences and trade-offs can help you write more efficient and readable JavaScript code.

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Windows

View result in a separate tab

Test name	Executions per second
hasown existing	15147126.0 Ops/sec
hasown missing	15326108.0 Ops/sec
undefined existing	16487622.0 Ops/sec
undefined missing	16638561.0 Ops/sec
destructure existing	16598158.0 Ops/sec
destructure missing	16664695.0 Ops/sec

Related benchmarks:

hasown vs undefined fixed (version: 0)

measures hasown vs undefined speed

Comparing performance of: hasown existing vs hasown missing vs undefined existing vs undefined missing vs destructure existing vs destructure missing

Created: 5 months ago by: Guest

Jump to the latest result

hasown existing

hasown missing

undefined existing

undefined missing

destructure existing

destructure missing

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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