Benchmark: cost of +1 level deeper prop access

Script Preparation code:

window.__obj = {
	num: 1,
	obj: {
		num: 1
	}
}

Tests:

direct access
const obj = window.__obj for (let i = 0; i < 10_000; i++) { obj.num }
+1 level access
const obj = window.__obj for (let i = 0; i < 10_000; i++) { obj.obj.num }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
direct access
+1 level access

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/116.0

Browser/OS: Firefox 116 on Windows

View result in a separate tab

Test name	Executions per second
direct access	111557.7 Ops/sec
+1 level access	108251.1 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark definition and test cases to help understand what's being tested.

**Benchmark Definition**

The benchmark is defined as the "cost of +1 level deeper prop access". This means that two microbenchmarks are created to measure the performance difference between accessing a property directly on an object versus accessing it through another level of nesting.

**Options Compared**

There are two options being compared:

1. **Direct Access**: `obj.num`
2. **+1 Level Access**: `obj.obj.num`

In direct access, we're accessing the `num` property directly on the root object (`window.__obj`). In +1 level access, we're accessing it through an intermediate object (`obj`) that contains another property (`obj`) which holds the actual value.

**Pros and Cons of Each Approach**

1. **Direct Access**:
	* Pros: Typically faster since there's no additional lookup involved.
	* Cons: May require more memory accesses if the root object is large or has many properties.
2. **+1 Level Access**:
	* Pros: Can be beneficial for certain data structures (e.g., trees, graphs) where the intermediate object provides a meaningful abstraction.
	* Cons: Requires an additional lookup and may incur performance overhead due to the indirect access.

**Library Usage**

The benchmark uses the `window.__obj` object as a test subject. This suggests that the benchmark is designed to measure the performance of accessing properties on an object in JavaScript, rather than a specific library or framework.

**Special JS Feature/Syntax**

There doesn't appear to be any special JavaScript features or syntax being tested in this benchmark. The microbenchmarks are relatively straightforward and focus on measuring the performance difference between direct and indirect property access.

**Alternatives**

If you're interested in exploring alternative approaches, here are a few options:

* **Using a different data structure**: Instead of using an object with nested properties, you could use an array or other data structure that requires different lookup patterns.
* **Implementing a caching mechanism**: You could introduce caching to reduce the number of lookups required for direct access, making it closer to +1 level access in terms of performance.
* **Using a specific library or framework**: Depending on your use case, you might want to test the performance of accessing properties using a library or framework like React's `this.props` or Angular's `$scope`.

Keep in mind that these alternatives would require modifying the benchmark definition and test cases to accommodate the new requirements.

Related benchmarks:

cost of +1 level deeper prop access (version: 0)

Comparing performance of: direct access vs +1 level access

Created: one year ago by: Registered User

Jump to the latest result

direct access

+1 level access

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):