Benchmark: Assigning an array to itself after mutating vs Destructuring it

HTML Preparation code:

<div id=''></div>

Tests:

Assign
let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]; numbers.push(13); numbers = numbers;
Destructure
let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12]; numbers = [...numbers, numbers.length + 1];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Assign
Destructure

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/108.0.0.0 Safari/537.36

Browser/OS: Chrome 108 on Linux

View result in a separate tab

Test name	Executions per second
Assign	27290702.0 Ops/sec
Destructure	24126276.0 Ops/sec

Autogenerated LLM Summary (model llama3.2:3b, generated 7 months ago):

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided benchmark.

**Benchmark Overview**

The benchmark is designed to compare two approaches: assigning an array to itself after mutating, and destructuring it. The goal is to measure which approach is faster on modern JavaScript engines.

**Script Preparation Code**

There is no script preparation code provided for this benchmark. This means that the test cases are not executed before running the tests, and the results are purely based on the execution time of the actual test cases.

**Individual Test Cases**

The benchmark consists of two test cases:

1. **"Assign"**: This test case assigns a new value to an array after modifying it by pushing a new element onto the end of the array. The array is then reassigned to itself.
2. **"Destructure"**: This test case uses the spread operator (`[...]`) to create a new array from the original array and add a new element at the end.

**Library Usage**

There is no explicit library usage in these test cases. However, the use of the spread operator (`[...]`) implies that the JavaScript engine is using some kind of optimization or feature that allows for more efficient array operations.

**Special JS Feature or Syntax**

The use of the spread operator (`[...]`) is a relatively modern JavaScript feature introduced in ECMAScript 2018. It allows for creating new arrays from existing ones by spreading elements into a new array.

**Pros and Cons**

* **Assign**: This approach involves modifying the original array, which can lead to slower performance due to the overhead of memory allocation and garbage collection.
* **Destructure**: This approach uses a spread operator, which is generally faster than reassigning an entire array. However, it may not work as expected if the original array has some internal structure or properties that are being modified.

**Pros of Destructuring:**

* Faster execution time due to reduced memory allocation and garbage collection overhead.
* More concise code, making it easier to read and maintain.

**Cons of Destructuring:**

* May not work correctly with arrays that have internal structures or properties that are being modified.
* Can be less intuitive for developers who are not familiar with the spread operator.

**Pros of Assigning:**

* More intuitive code for developers who are familiar with reassigning entire arrays.
* May work correctly with arrays that have internal structures or properties that are being modified.

**Cons of Assigning:**

* Slower execution time due to memory allocation and garbage collection overhead.
* More verbose code, making it less readable and maintainable.

**Alternatives**

Other approaches could be used to measure the performance difference between assigning an array to itself after mutating and destructuring it. Some alternatives include:

* Using a different data structure, such as an object or a linked list.
* Adding more elements to the array before reassigning or destructuring it.
* Introducing noise into the code to simulate real-world scenarios.
* Comparing performance with other programming languages or frameworks.

However, these alternative approaches may not accurately represent the specific use case being tested (i.e., assigning an array to itself after mutating vs. destructuring), and may introduce additional variables that can affect the results.

Related benchmarks:

Assigning an array to itself after mutating vs Destructuring it (version: 0)

Comparing performance of: Assign vs Destructure

Created: 2 years ago by: Guest

Jump to the latest result

Assign

Destructure

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 7 months ago):