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

Script Preparation code:

var arr = [10000];

Tests:

unshift
for (let i = 0; i < 10000; i++){ arr.unshift(i); }
push + reverse
for (let i = 0; i < 10000; 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:

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

LLMs can make mistakes. Check important info.

**What is being tested?**

MeasureThat.net is testing the performance of two different approaches to add elements to an array in JavaScript: `arr.unshift()` and `arr.push()`, followed by reversing the array using `arr.reverse()`. The benchmark is designed to measure the execution time of these operations on a large array (10,000 elements) to determine which approach is faster.

**Options compared**

The two options being compared are:

1. **unshift**: This method adds an element to the beginning of the array.
2. **push + reverse**: This approach first adds an element to the end of the array using `arr.push()`, and then reverses the array using `arr.reverse()`.

**Pros and Cons**

* **unshift**: Pros:
	+ Can be faster for adding elements to the beginning of the array, as it only requires a single operation.
	+ Can reduce the number of array resizing operations required when the array grows or shrinks.
* Cons:
	+ Reverses the entire array, which can lead to performance issues if the array is very large.
	+ May not be suitable for cases where the array needs to maintain its original order.
* **push + reverse**: Pros:
	+ Maintains the original order of the elements.
	+ Allows the array to grow or shrink without requiring significant resizing operations.
* Cons:
	+ Requires two separate operations: adding an element and reversing the array.
	+ May be slower for small arrays due to the overhead of the `reverse()` method.

**Library usage**

There is no explicit library mentioned in the benchmark definition, but it's likely that the built-in JavaScript `Array` object is being used.

**Special JS feature or syntax**

The benchmark defines two test cases using a **for...of** loop and a primitive numeric type (`let i = 0;`) to iterate over an array. This is a modern JavaScript feature introduced in ECMAScript 2015 (ES6) for iterating over arrays and other iterable objects.

**Other alternatives**

If the developers of MeasureThat.net wanted to include additional test cases, they might consider:

* Using different data types or structures (e.g., object arrays, sets)
* Exploring caching effects on array operations
* Investigating performance differences between modern JavaScript engines (e.g., SpiderMonkey, V8, Chakra)
* Adding support for other algorithms or approaches to array manipulation

Keep in mind that these alternatives would require significant changes to the benchmark definition and test cases.

Related benchmarks:

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

Comparing performance of: unshift vs push + reverse

Created: 4 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):