Benchmark: Replacing array - MeasureThat.net

Script Preparation code:

var arr = [...Array(10000)].map((_, i) => i + 1)

Tests:

splice Infinity
arr.splice(0, Infinity, ...[1,2,3])
splice array.length
arr.splice(0, arr.length, ...[1,2,3])
length 0
arr.length = 0 arr.push(...[1,2,3])

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
splice Infinity
splice array.length
length 0

Fastest: N/A

Slowest: N/A

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/121.0.0.0 Safari/537.36

Browser/OS: Chrome 121 on Windows

View result in a separate tab

Test name	Executions per second
splice Infinity	3415739.2 Ops/sec
splice array.length	4859192.5 Ops/sec
length 0	4137545.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided JSON data and explain what's being tested.

**Benchmark Definition**

The benchmark is defined by two parts:

1. **Script Preparation Code**: This code initializes an array `arr` with 10,000 elements, where each element is a number incremented by its index (i.e., `[1, 2, 3, ..., 9999]`). This creates a large array that will be modified in the subsequent steps.
2. **Html Preparation Code**: This field is empty (`null`) and doesn't seem to affect the benchmark.

**Individual Test Cases**

There are three test cases, each with a different approach to modifying the `arr` array:

1. **splice Infinity**: This test case uses `arr.splice(0, Infinity, ...[1,2,3])`, which replaces the first element of the array with an infinite sequence of numbers `[1, 2, 3]`. This will push the existing elements beyond the end of the array, potentially causing buffer overflows or other issues.
2. **splice array.length**: This test case uses `arr.splice(0, arr.length, ...[1,2,3])`, which removes the first element(s) of the array and replaces them with a new sequence `[1, 2, 3]`. This is likely intended to test the performance of removing elements from an array.
3. **length 0**: This test case uses `arr.length = 0\r\narr.push(...[1,2,3])`, which resets the length of the array to zero and then pushes a new sequence `[1, 2, 3]` onto it. This tests the performance of resetting an array's length.

**Libraries**

None of the test cases appear to use external libraries explicitly. However, some browsers (like Chrome) may have internal library functions that are being called during these operations.

**Special JavaScript Features/Syntax**

There is one notable feature:

* The `...` operator (also known as "spread syntax") is used to create arrays and pass them as arguments. This was introduced in ECMAScript 2015 (ES6) and has since become a standard part of the language.
* The `\r\n` escape sequence is used to denote line breaks, which is specific to Windows-style newline characters.

**Pros and Cons**

Each approach has its pros and cons:

1. **splice Infinity**:
	* Pros: Tests performance with an extreme case (infinite sequence).
	* Cons: May cause buffer overflows or other issues due to the large sequence.
2. **splice array.length**:
	* Pros: Tests performance of removing elements from an array.
	* Cons: Limited in its impact, as only a small portion of the original array is removed.
3. **length 0**:
	* Pros: Tests performance with an extreme case (resetting array length).
	* Cons: Similar to `splice Infinity`, may cause issues due to the large push operation.

**Alternatives**

Other alternatives could include:

1. Modifying the array using other methods, such as `concat()`, `push()`, or `unshift()`.
2. Using a different data structure (e.g., a linked list) instead of an array.
3. Performing a similar benchmark with a smaller dataset.

It's worth noting that this specific benchmark may not be representative of real-world use cases, and its purpose is likely to test the performance of specific browser implementations under various conditions.

Related benchmarks:

Replacing array (version: 0)

Replacing array with: - splice infinity - splice arr.length - length reset + push

Comparing performance of: splice Infinity vs splice array.length vs length 0

Created: 2 years ago by: Registered User

Jump to the latest result

splice Infinity

splice array.length

length 0

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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