Benchmark: Reference vs Dereference with object containing array of 10 000 elements

Tests:

Reference
const size = 10000; const obj = { arr: Array(size).fill(1) }; let res; const ref = obj.arr; for (let i = 0; i < size; i++) { res = ref[i]; }
Dereference
const size = 10000; const obj = { arr: Array(size).fill(1) }; let res; for (let i = 0; i < size; i++) { res = obj.arr[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reference
Dereference

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; rv:133.0) Gecko/20100101 Firefox/133.0

Browser/OS: Firefox 133 on Linux

View result in a separate tab

Test name	Executions per second
Reference	20799.2 Ops/sec
Dereference	20342.4 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark test cases for you.

**What is tested?**

The benchmark tests two approaches to accessing elements in an array within an object:

1. **Reference**: This approach stores a reference to the `arr` property of the object in a separate variable, `ref`, and then iterates over the array using this reference.
2. **Dereference**: This approach accesses the `arr` property directly on the object (`obj`) and uses its index to access each element.

**Options compared**

The benchmark compares these two approaches:

* **Reference**: Using a separate variable to store a reference to the array element
* **Dereference**: Accessing the array element directly on the object

**Pros and Cons of each approach:**

1. **Reference**:
	* Pros:
		+ Might be slightly faster due to potential optimization by the JavaScript engine for accessing an array through a separate variable.
		+ Could allow for better caching or memoization opportunities, potentially leading to performance gains.
	* Cons:
		+ May introduce additional memory usage due to the extra variable.
2. **Dereference**:
	* Pros:
		+ Typically more straightforward and easier to understand.
		+ Might not introduce any significant overhead in terms of memory or execution time.
	* Cons:
		+ May be slightly slower due to the need to access the array element through the object's property.

**Library/JavaScript feature**

There is no library used in this benchmark. However, it does utilize some JavaScript syntax features:

* **let**, **const**, and **for` loops are standard JavaScript syntax.
* The `Array(size).fill(1)` expression creates a new array with `size` elements, filled with the value `1`.

**Other considerations**

The benchmark focuses on measuring the performance difference between these two approaches. To get accurate results, it's essential to ensure that:

* Both the reference and dereference implementations are identical, except for the approach being tested.
* The script preparation code is minimal, avoiding any potential side effects or optimizations.
* The HTML preparation code is also minimal, as its impact on performance might be negligible.

**Alternative approaches**

Other alternatives could include:

* Using `Array.prototype.forEach()` instead of a traditional `for` loop
* Employing more advanced optimization techniques, such as inlining the array access or using a specialized array-iterator
* Utilizing different data structures, like a typed array or a buffer

However, these alternative approaches are not explicitly tested in this benchmark.

Related benchmarks:

Reference vs Dereference with object containing array of 10 000 elements (version: 0)

Comparing performance of: Reference vs Dereference

Created: 7 years ago by: Registered User

Jump to the latest result

Reference

Dereference

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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