Benchmark: Push&assign vs Unshift

Script Preparation code:

var arr1;
var arr2;

Tests:

Push
arr1 = [1, 2, 3]; arr2 = [4, 5, 6]; arr1.push(...arr2); arr2 = arr1;
Unshift
arr1 = [1, 2, 3]; arr2 = [4, 5, 6]; arr2.unshift(...arr1);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Push
Unshift

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36 OPR/113.0.0.0

Browser/OS: Opera 113 on Windows

View result in a separate tab

Test name	Executions per second
Push	2692897.2 Ops/sec
Unshift	3230785.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll explain the JavaScript microbenchmark provided by MeasureThat.net.

**Benchmark Overview**

The benchmark tests two approaches for array manipulation: `push` and `unshift`. Both approaches involve creating an initial array (`arr1`) and another array (`arr2`) with some values. The test then measures the performance of each approach to perform one of two operations:

1. Assigning `arr2` to `arr1`, followed by pushing all elements of `arr2` onto `arr1`.
2. Prepending all elements of `arr1` to `arr2`.

**Options Compared**

Two options are compared in this benchmark:

1. **Push**: This approach uses the `push()` method to add elements to the end of an array.
2. **Unshift**: This approach uses the `unshift()` method to add elements to the beginning of an array.

**Pros and Cons of Each Approach**

* **Push**:
	+ Pros: Generally faster, as it only needs to iterate over the elements to be pushed, without the overhead of inserting at a specific position.
	+ Cons: Requires iterating over the elements to be pushed, which can lead to slower performance for large arrays if `push()` is not optimized.
* **Unshift**:
	+ Pros: More efficient when pushing multiple elements from the beginning of an array, as it avoids the overhead of inserting at a specific position and only needs to update the length of the array.
	+ Cons: Requires updating the length of the array, which can be slower than `push()` for large arrays. Additionally, it may require more memory allocation.

**Library and Purpose**

There is no explicit library mentioned in the benchmark definition. However, `push()` and `unshift()` are built-in JavaScript methods that operate on arrays.

**Special JS Feature or Syntax (None)**

There are no special features or syntax used in this benchmark.

**Other Alternatives**

If you need to perform similar operations, other alternatives could be:

* Using a library like Lodash, which provides a `concat()` method for concatenating arrays.
* Using the spread operator (`...`) with `push()` and `unshift()`, e.g., `arr1.push(...arr2)` or `arr1.unshift(...arr2)`.
* Using `splice()` to insert elements at specific positions in an array.

Keep in mind that these alternatives may have different performance characteristics, depending on the specific use case and the implementation of the library or method used.

Related benchmarks:

Push&assign vs Unshift (version: 1)

Comparing performance of: Push vs Unshift

Created: one year ago by: Registered User

Jump to the latest result

Push

Unshift

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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