Benchmark: splice twice VS shift + pop

Script Preparation code:

var list = [];
for (var i = 0; i < 1000 * 1000; i++) {
  list.push(i);
}

Tests:

splice twice
list = list.splice(1, 1); list = list.splice(list.length - 1, 1)
shift + pop
list.shift(); list.pop();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
splice twice
shift + pop

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

I'd be happy to help you understand the JavaScript microbenchmark on MeasureThat.net.

**Overview**

The benchmark is designed to compare the performance of two different approaches: `splice` and `shift + pop`. The test case creates an array of 1 million elements and then applies each approach repeatedly. The goal is to measure which approach is faster.

**Benchmark Definition JSON**

The benchmark definition JSON contains three main parts:

* **Name**: A descriptive name for the benchmark.
* **Description**: A brief description of the benchmark (in this case, "100k list").
* **Script Preparation Code**: A JavaScript code snippet that sets up the test environment. In this case, it creates an empty array `list` and populates it with 1 million elements.

The `Html Preparation Code` field is empty, indicating that no HTML-related setup is required for this benchmark.

**Individual Test Cases**

There are two individual test cases:

* **splice twice**: This test case applies the `splice` method twice to the array. The first call removes the first element (index 0), and the second call removes the last element (index -1).
* **shift + pop**: This test case applies the `shift()` and `pop()` methods sequentially. `shift()` removes and returns the first element, while `pop()` removes and returns the last element.

**Options Compared**

The two approaches being compared are:

* **splice**: The built-in JavaScript method for removing elements from an array.
* **shift + pop**: A sequential approach that uses the `shift()` and `pop()` methods to remove elements.

**Pros and Cons**

Here's a brief analysis of each approach:

* **splice**:
	+ Pros: Efficient and optimized by the browser engine.
	+ Cons: Can be slower for small arrays due to the overhead of creating a new array fragment.
* **shift + pop**:
	+ Pros: Simple and easy to implement.
	+ Cons: May not be as efficient as `splice` for large arrays, as it involves two separate operations.

**Library Used**

There is no library explicitly used in this benchmark. The `splice()` method is a built-in JavaScript function.

**Special JS Feature or Syntax**

None mentioned explicitly.

**Other Considerations**

When interpreting the benchmark results, keep in mind that:

* **Browser Engine Optimization**: Modern browser engines have optimized the `splice` method for performance.
* **Array Fragmentation**: For small arrays, using `splice()` can lead to array fragmentation, which may impact performance.
* **Test Environment**: The test environment (e.g., Chrome 99 on a Windows Desktop) might influence the results.

**Alternatives**

If you're interested in exploring other benchmarking approaches or alternatives, here are some options:

* **V8 Benchmark Suite**: A collection of microbenchmarks for V8, including some similar to this one.
* **JSPerf**: A popular tool for running JavaScript benchmarks and comparing performance across different browsers and versions.
* **Benchmark.js**: A lightweight library for creating and running JavaScript benchmarks.

Remember that benchmarking results can vary depending on the test environment, browser engine, and other factors. Always consider these when interpreting and applying benchmark results to your own projects.

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36

Browser/OS: Chrome 99 on Windows

View result in a separate tab

Test name	Executions per second
splice twice	1623747.5 Ops/sec
shift + pop	5892135.0 Ops/sec

Related benchmarks:

splice twice VS shift + pop (version: 0)

100k list

Comparing performance of: splice twice vs shift + pop

Created: 5 years ago by: Guest

Jump to the latest result

splice twice

shift + pop

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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