Benchmark: Insert multiple items in an array

Script Preparation code:

var array = Array.from({ length: 1000 }).map((val, i) => i);var array2 = Array.from({ length: 1000 }).map((val, i) => i);

Tests:

Splice
array.splice(array.length, 0, array2);
Unshift
array.unshift(array2)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Splice
Unshift

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

I'd be happy to explain the benchmarking test for you.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that tests the performance of two different array manipulation methods: `splice` and `unshift`. The goal of this benchmark is to compare the execution speed of these two approaches when inserting an array into another array.

**Options compared:**

There are two options compared in this benchmark:

1. **`array.splice(array.length, 0, array2)`**: This method inserts a new element at the beginning of the `array` using `splice`. The `length` parameter specifies the position where the new element should be inserted, and the `array2` is passed as an argument to insert it.
2. **`array.unshift(array2)`**: This method inserts a new element at the beginning of the `array` using the `unshift()` method.

**Pros and Cons:**

* **`splice` approach:**
	+ Pros:
		- Allows for more control over insertion position
		- Can be used to remove elements from the end of an array as well
	+ Cons:
		- Can be slower due to the overhead of searching for the desired index
* **`unshift` approach:**
	+ Pros:
		- Faster than `splice`, especially when inserting at the beginning
		- More concise and readable code
	+ Cons:
		- Less control over insertion position

**Library and purpose:**

In this benchmark, the `Array.from()` method is used to create a new array with a specified length and populate it with values. The `map()` function is also used to transform each value in the array.

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

**Other considerations:**

* The benchmark uses a relatively small array size of 1000 elements, which may not be representative of real-world scenarios where arrays can grow much larger.
* The benchmark runs on a desktop platform (Windows), which may affect the results compared to running on mobile devices or other platforms.
* The benchmark is run using Chrome 102 as the browser and Windows as the operating system.

**Alternatives:**

There are several alternatives for testing array manipulation performance, including:

1. **`concat()`**: Instead of using `splice` or `unshift`, you can use `array.concat(array2)` to concatenate two arrays.
2. **`Array.prototype.set()`**: Introduced in ECMAScript 2015 (ES6), `set()` allows you to insert elements at a specific position in an array.
3. **Native Web Workers**: You can run the benchmark using Web Workers, which allow you to execute JavaScript code in parallel, potentially improving performance.
4. **Benchmarking libraries**: There are several third-party benchmarking libraries available, such as Benchmark.js or js-benchmark, that provide more comprehensive and robust testing capabilities.

Keep in mind that the choice of alternative depends on your specific use case and requirements.

Related benchmarks:

Insert multiple items in an array (version: 0)

Comparing performance of: Splice vs Unshift

Created: 3 years ago by: Guest

Jump to the latest result

Splice

Unshift

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):