Benchmark: multiple shift vs splice

Script Preparation code:

var arr = [];
for (i = 0; i < 1000; i++) {
    arr.push(i);
}
var arr2 = [];
arr2.push(arr.slice(0, 199))
arr2.push(arr.slice(200, 399))
arr2.push(arr.slice(400, 599))
arr2.push(arr.slice(600, 799))
arr2.push(arr.slice(800, 999))

Tests:

splice
arr.splice(0,200);
shift
arr2.shift();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
splice
shift

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 2 years ago)

User agent: Mozilla/5.0 (Android 14; Mobile; rv:120.0) Gecko/120.0 Firefox/120.0

Browser/OS: Firefox Mobile 120 on Android

View result in a separate tab

Test name	Executions per second
splice	21471972.0 Ops/sec
shift	166942624.0 Ops/sec

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 benchmark and its options.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmarking test case on MeasureThat.net. The test compares two different approaches: using `splice()` with a specified amount, and removing elements from an array using the `shift()` method.

**Script Preparation Code**

The script preparation code creates two arrays, `arr` and `arr2`. The purpose of these arrays is to simulate a complex data structure that needs to be modified frequently. Specifically:

* `arr` is created with 1000 elements, each initialized with its index value.
* `arr2` is created by slicing `arr` into four smaller parts using the `slice()` method. This simulates a scenario where multiple sections of an array need to be modified.

**Options Compared**

The benchmark tests two options:

1. **Splice**: This option uses the `splice()` method to remove elements from `arr`. The `splice()` method modifies the original array by removing specified elements and shifting subsequent elements down.
2. **Shift**: This option removes elements from `arr` using the `shift()` method.

**Pros and Cons of Each Approach**

1. **Splice**:
	* Pros:
		+ Can remove multiple elements at once, which might be more efficient for large arrays.
		+ Allows for more flexibility in modifying the array's structure.
	* Cons:
		+ Modifies the original array, which can lead to unexpected behavior if the array is not properly cloned or copied.
		+ Can be slower than `shift()` due to the overhead of shifting elements down.
2. **Shift**:
	* Pros:
		+ Does not modify the original array, preserving its integrity.
		+ Faster than `splice()` since it only removes the first element from the array.
	* Cons:
		+ Requires repeated calls to remove multiple elements, which can be slower for large arrays.

**Library**

In this benchmark, no specific library is used. However, if a library like Lodash was used in the script preparation code or the test cases, it would be worth noting that libraries can add complexity and potentially introduce performance overhead.

**Special JS Feature/Syntax**

There are no special JavaScript features or syntax used in this benchmark. It only employs standard JavaScript methods (`slice()`, `splice()`, and `shift()`).

**Alternatives**

Other alternatives to the `splice()` method include:

* `concat()`: Creates a new array by concatenating two arrays. This can be slower than `splice()` for large arrays.
* `setLength()`: Sets the length of an array, effectively removing elements from the end. However, this method is not widely supported and may have performance implications.

In general, when choosing between these methods, consider the specific requirements of your use case, such as:

* Performance: If speed is critical, using `shift()` might be a better option.
* Data Integrity: If preserving the original array's structure is essential, using `splice()` with caution and proper cloning or copying may be necessary.
* Code Readability: Choose the method that best reflects your code's intent and readability.

Keep in mind that the performance differences between these methods can vary depending on the specific JavaScript engine, browser, or platform being used.

Related benchmarks:

multiple shift vs splice (version: 0)

-

Comparing performance of: splice vs shift

Created: 3 years ago by: Guest

Jump to the latest result

splice

shift

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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