Benchmark: Split vs Substr+IndexOf Performance

Script Preparation code:

var s1 = "28.9% CPU samples were in `Array.Sort` called from `DiagService.Controllers.PerfCPUController.CpuTask`. We expect this value to be less than 0.7%."

Tests:

Split
var resultSplit = s1.split[1];
Substring
var resultSubstr = s1.substring(s1.indexOf('`') + 1, s1.indexOf('`', s1.indexOf('`') + 1))

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Split
Substring

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:148.0) Gecko/20100101 Firefox/148.0

Browser/OS: Firefox 148 on Windows

View result in a separate tab

Test name	Executions per second
Split	37031792.0 Ops/sec
Substring	43452724.0 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 and explain what's being tested in this JavaScript microbenchmark.

**Benchmark Overview**

The benchmark compares the performance of two approaches to extract a substring from a given string: `split` and `substring + indexOf`. The test aims to determine which approach is faster.

**Options Compared**

Two options are compared:

1. **`split`**: This method splits a string into an array of substrings using a specified separator (in this case, no separator). It then returns the second element of the resulting array.
2. **`substring + indexOf`**: This approach uses the `indexOf` method to find the index of the first occurrence of a specific substring (`' '`), and then uses the `substring` method to extract the substring from the original string.

**Pros and Cons**

1. **`split`**:
	* Pros: Simple, efficient, and widely supported.
	* Cons: May not be suitable for strings without a separator, and it can return an array with additional elements if the separator is present multiple times.
2. **`substring + indexOf`**:
	* Pros: Can handle strings without a specific substring to find, and it returns only the extracted substring.
	* Cons: Requires two method calls ( `indexOf` followed by `substring` ), which can lead to overhead.

**Library/Functionality Used**

None of the test cases use any libraries or external functions. The functionality is built-in to JavaScript.

**Special JS Features/Syntax**

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

**Other Alternatives**

Other approaches to extract a substring from a string could be:

* Using regular expressions (e.g., `s1.match(/\s/g)[0]`)
* Using the `slice` method (e.g., `s1.slice(s1.indexOf(' ') + 1, s1.indexOf(' ') + 2)`)
* Using a custom loop to iterate through the string and find the substring

However, these alternatives are not being tested in this specific benchmark.

**Benchmark Preparation Code**

The provided "Script Preparation Code" is used to prepare the input string `s1` before running the benchmarks. It's used to extract the CPU usage percentage from a string, which seems unrelated to the actual benchmarking task.

I hope this explanation helps you understand what's being tested in this JavaScript microbenchmark!

Related benchmarks:

Split vs Substr+IndexOf Performance (version: 0)

Comparing performance of: Split vs Substring

Created: 4 years ago by: Guest

Jump to the latest result

Split

Substring

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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