Benchmark: unshift vs push and reverse

Tests:

unshift
let array = []; for (let i = 0; i < 200; i++) { array.unshift(i); }
push and reverse
let array = []; for (let i = 0; i < 200; i++) { array.push(i); } array.reverse()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
unshift
push and reverse

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 9 months ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:140.0) Gecko/20100101 Firefox/140.0

Browser/OS: Firefox 140 on Linux

View result in a separate tab

Test name	Executions per second
unshift	117520.5 Ops/sec
push and reverse	1208899.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and its test cases.

**Benchmark Overview**

The benchmark measures the performance difference between using `unshift()` and `push()` with subsequent reversal of an array in JavaScript. The benchmark prepares an empty array, iterates 200 times, adding a value to either the beginning (`unshift()`) or end (`push()`) of the array, and then reverses the array.

**Options Compared**

There are two main approaches being compared:

1. **Unshift**: Using `array.unshift(i)`, which adds an element to the beginning of the array.
2. **Push**: Using `array.push(i)`, followed by reversing the array with `array.reverse()`.

**Pros and Cons of Each Approach**

* **Unshift**:
	+ Pros: May be faster for certain use cases, as it avoids the overhead of creating a temporary array during the push operation.
	+ Cons: Reversing the array after pushing can lead to poor cache locality, reducing performance. Additionally, unshift() may allocate more memory than necessary if the array is large.
* **Push**:
	+ Pros: Faster and more efficient for reversing arrays after pushes, as it avoids the overhead of creating a temporary array.
	+ Cons: May be slower due to the push operation itself.

**Library/Functionality Used**

There is no explicit library or functionality mentioned in the provided JSON. However, `array.unshift()` and `array.push()` are built-in JavaScript methods.

**Special JS Feature/Syntax**

No special JavaScript features or syntax are used in this benchmark.

**Other Considerations**

* The benchmark measures the performance difference between these two approaches, so a good understanding of performance optimization techniques is essential for interpreting the results.
* This benchmark may not be representative of all scenarios, as it only tests a specific use case involving array operations. Other benchmarks might focus on different aspects, such as memory allocation or garbage collection.

**Alternatives**

For similar performance benchmarks:

1. **Micro-benchmarking frameworks**: Tools like Benchmark.js or js-benchmark can help create and run microbenchmarks.
2. **JavaScript performance profiling tools**: Instruments like Chrome DevTools' Performance tab or Node.js Inspector can provide detailed insights into JavaScript performance.
3. **Benchmarking platforms**: Websites like MeasureThat.net (the current benchmark) or GitHub's Code Golf challenge series offer a platform to share and compare benchmarks.

Keep in mind that the specific context of this benchmark might be related to particular use cases, such as data processing or scientific computing.

Related benchmarks:

unshift vs push and reverse (version: 0)

Comparing performance of: unshift vs push and reverse

Created: 4 years ago by: Guest

Jump to the latest result

unshift

push and reverse

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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