Benchmark: Spread Operator: Object

Tests:

Spread object at head
const object = {a: 1, b: 2, c: 3}; const result = {...object, d: 4};
Spread object at tail
const object = {a: 1, b: 2, c: 3}; const result = {d: 4, ...object};

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Spread object at head
Spread object at tail

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'll explain the benchmark and its components.

**Benchmark Definition**

The provided JSON represents a JavaScript microbenchmark that measures the performance of the spread operator in JavaScript. The benchmark is designed to accelerate the JavaScript spread operator, which is used to create new objects by spreading properties from an existing object.

**Options Compared**

In this benchmark, two approaches are compared:

1. **Spread Object at Head**: This approach uses the syntax `const result = {...object, d: 4};`, where the spread operator is applied to the `object` variable before assigning it to a new variable `result`. The spread operator creates a new object and copies all properties from `object` except for `d`.
2. **Spread Object at Tail**: This approach uses the syntax `const result = {d: 4, ...object};`, where the spread operator is applied after assigning values to `result`.

**Pros and Cons of Each Approach**

1. **Spread Object at Head**:
	* Pros:
		+ May be slightly more efficient since it avoids the need to create a new object with all properties from `object`.
		+ Can take advantage of some optimizations in modern JavaScript engines.
	* Cons:
		+ Requires creating a temporary variable, which can lead to additional memory allocation and deallocation overhead.
2. **Spread Object at Tail**:
	* Pros:
		+ Only creates a new object with the required properties (`d: 4`), reducing memory allocation overhead.
	* Cons:
		+ May require more iterations in the JavaScript engine's parser, potentially leading to slower performance.

**Library and Special JS Features**

None of the test cases use any external libraries or special JavaScript features. The benchmark only relies on built-in JavaScript functionality.

**Other Alternatives**

To accelerate the spread operator, other approaches could be explored, such as:

* Using a custom implementation in native code (e.g., WebAssembly)
* Optimizing the JavaScript engine's parser to handle the spread operator more efficiently
* Utilizing SIMD instructions (Single Instruction, Multiple Data) to parallelize operations on arrays

However, these alternatives are not included in this benchmark and require further investigation to determine their feasibility and performance benefits.

I hope this explanation helps!

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/90.0.4430.212 Safari/537.36

Browser/OS: Chrome 90 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Spread object at head	1909690.5 Ops/sec
Spread object at tail	12882151.0 Ops/sec

Related benchmarks:

Spread Operator: Object (version: 1)

How To Accelerate the JavaScript Spread Operator https://dmitripavlutin.com/javascript-spread-operator-performance-optimization/

Comparing performance of: Spread object at head vs Spread object at tail

Created: 3 years ago by: Registered User

Jump to the latest result

Spread object at head

Spread object at tail

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):