Benchmark: arr unshift vs push + reverse ( array 100)

Script Preparation code:

var arr = [10];

Tests:

unshift
for (let i = 0; i < 100; i++){ arr.unshift(i); }
push + reverse
for (let i = 0; i < 100; i++){ arr.push(i); } arr.reverse();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
unshift
push + reverse

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data to understand what is being tested in this JavaScript microbenchmark.

**Benchmark Definition**
The benchmark definition specifies that two different approaches are being compared:

1. `unshift`: This approach uses the `arr.unshift(i)` method to add elements to the beginning of an array.
2. `push + reverse`: This approach uses the `arr.push(i)` method to add elements to the end of the array, followed by reversing the array using `arr.reverse()`.

**Options Compared**

The two options being compared are:

* `unshift`
* `push + reverse`

**Pros and Cons**

Here's a brief overview of the pros and cons of each approach:

* **`unshift`**:
	+ Pros: Can be faster for small arrays, as it only requires shifting elements to make space.
	+ Cons: Can be slower for large arrays, as it involves more overhead (e.g., copying elements).
* `push + reverse`:
	+ Pros: Generally faster for large arrays, as reversing the array can be done in a single operation (i.e., using `reverse()`).
	+ Cons: Requires two separate operations (adding elements and reversing), which can lead to additional overhead.

**Library and Purpose**

In this benchmark, no specific libraries are used beyond the built-in JavaScript methods (`unshift`, `push`, and `reverse`).

**Special JS Feature or Syntax**
This benchmark does not use any special JavaScript features or syntax. It only uses standard JavaScript constructs.

**Other Alternatives**

If you were to rewrite this benchmark using different approaches, some alternatives could include:

* Using `splice()` instead of `unshift` or `push`
* Using a data structure like a linked list instead of an array
* Using a different algorithm for adding elements to the array (e.g., using `concat()` or `slice()`)
* Using parallel processing or multithreading to speed up the tests

**Benchmark Preparation Code**

The provided benchmark preparation code initializes an array `arr` with a single element (`10`) before running the test cases. This allows the benchmarks to start from a consistent state.

**Individual Test Cases**

The two individual test cases are:

1. `unshift`: This test case runs 100 iterations of adding elements to the beginning of the array using `unshift`.
2. `push + reverse`: This test case runs 100 iterations of adding elements to the end of the array using `push`, followed by reversing the array.

The latest benchmark result shows the execution per second for each browser and device platform, which can be used to compare the performance of the two approaches.

Related benchmarks:

arr unshift vs push + reverse ( array 100) (version: 0)

Comparing performance of: unshift vs push + reverse

Created: 2 years ago by: Guest

Jump to the latest result

unshift

push + reverse

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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