Benchmark: 2substr - MeasureThat.net

Tests:

first
let s = "helo"; s.replace(s.substr(0,1), s.substr(0,1).toUpperCase());
second
let s = "helo"; s[0].toUpperCase() + s.substr(1);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
first
second

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):

LLMs can make mistakes. Check important info.

I'd be happy to explain what's being tested in the provided benchmark.

**Benchmark Overview**

MeasureThat.net is a website that allows users to create and run JavaScript microbenchmarks. The goal of this benchmark is to measure the performance of different approaches for extracting a specific substring from a string.

**What is being tested?**

The benchmark tests two approaches for extracting the first character of a string:

1. `s.substr(0, 1)` (Approach 1)
2. `s[0].toUpperCase() + s.substr(1)` (Approach 2)

**Options Compared**

The benchmark compares the performance of these two approaches on a sample string "hello".

**Pros and Cons of Each Approach:**

* **Approach 1: `s.substr(0, 1)`**
	+ Pros:
		- Simple and straightforward.
	+ Cons:
		- May involve creating a new array or substring object, which can be memory-intensive for large strings.
		- May not be the most efficient way to extract a single character from a string.
* **Approach 2: `s[0].toUpperCase() + s.substr(1)`**
	+ Pros:
		- Only involves accessing and manipulating existing characters in the original string, which can be more memory-efficient.
		- May be faster since it doesn't involve creating new objects or arrays.
	+ Cons:
		- More complex and may require a higher level of JavaScript proficiency.

**Library and Special JS Features**

There are no libraries or special JavaScript features used in this benchmark. The code only uses built-in JavaScript methods and syntax.

**Alternative Approaches**

Other possible approaches to extract the first character from a string might include:

* Using `s.charAt(0)` (which is equivalent to `s[0]` but may be more efficient)
* Using a regular expression (`s.match(/^\w/)[0]`)
* Using a custom function or utility library specifically designed for substring extraction

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

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:73.0) Gecko/20100101 Firefox/73.0

Browser/OS: Firefox 73 on Linux

View result in a separate tab

Test name	Executions per second
first	14595094.0 Ops/sec
second	950972480.0 Ops/sec

Related benchmarks:

2substr (version: 0)

Comparing performance of: first vs second

Created: 4 years ago by: Guest

Jump to the latest result

first

second

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model llama3.2:3b, generated 26 days ago):