Benchmark: Last char trim speed

Tests:

substr index access
let matchstring = '?really just a string/'; let lastChar = matchstring[matchstring.length -1]; if (lastChar === '/') { let result = matchstring.substring(0, -1); }
substr charAt access
let matchstring = '?really just a string/'; let lastChar = matchstring.charAt(-1); if (lastChar === '/') { let result = matchstring.substring(0, -1); }
slice index
let matchstring = '?really just a string/'; let lastChar = matchstring[matchstring.length -1]; if (lastChar === '/') { let result = matchstring.slice(0, -1); }
slice charat
let matchstring = '?really just a string/'; let lastChar = matchstring.charAt(-1); if (lastChar === '/') { let result = matchstring.slice(0, -1); }
replace
let matchstring = '?really just a string/'; let result = matchstring.replace(/\/+$/, '');

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
substr index access
substr charAt access
slice index
slice charat
replace

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36

Browser/OS: Chrome 127 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
substr index access	162876128.0 Ops/sec
substr charAt access	102118224.0 Ops/sec
slice index	163643344.0 Ops/sec
slice charat	103859592.0 Ops/sec
replace	24952670.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks on MeasureThat.net.

**Benchmark Overview**

The provided benchmark measures the speed of different approaches to access the last character of a string in JavaScript. The benchmark consists of four test cases:

1. `substr index access`
2. `substr charAt access`
3. `slice index`
4. `replace`

Each test case has a similar input: a fixed-length string with a trailing `/` character.

**Options Compared**

The benchmark compares the speed of different approaches to access the last character of the string:

1. **Substring**: Using `matchstring.substring(0, -1)` to extract all characters up to the second last one and then removing the last character.
2. **charAt**: Using `matchstring.charAt(-1)` to directly access the last character.
3. **Slice**: Using `matchstring.slice(0, -1)` to extract all characters up to the second last one and then removing the last character.

**Pros and Cons of Each Approach**

1. **Substring**: This approach is straightforward but may be slower due to the overhead of creating a new string object.
	* Pros: Easy to understand, no specific syntax knowledge required.
	* Cons: May involve additional memory allocations.
2. **charAt**: This approach uses a direct method to access the last character.
	* Pros: Fast, efficient, and concise.
	* Cons: Requires understanding of negative indices in JavaScript.
3. **Slice**: This approach uses `slice()` method to extract all characters up to the second last one and then removing the last character.
	* Pros: Similar speed to `charAt`, avoids creating a new string object.
	* Cons: May require more computational power due to the slice operation.

**Other Considerations**

* The benchmark does not consider other factors that may affect performance, such as:
	+ String length (shorter strings may behave differently).
	+ Browser or environment-specific optimizations.
	+ Potential optimizations using `exec()` method instead of `charAt` for specific use cases.
* No consideration is given to memory usage, which could be a significant factor in some scenarios.

**Library Usage**

None of the test cases explicitly use any external libraries. However, some JavaScript engines (like SpiderMonkey) may optimize string operations internally, potentially affecting performance.

**Special JS Features or Syntax**

The benchmark does not require special knowledge of advanced JavaScript features like:

* Promises
* Async/await
* `for...of` loops

However, it does rely on negative indices (`-1`) for accessing the last character, which may be a point of discussion among developers.

Related benchmarks:

Last char trim speed (version: 0)

Comparing performance of: substr index access vs substr charAt access vs slice index vs slice charat vs replace

Created: one year ago by: Guest

Jump to the latest result

substr index access

substr charAt access

slice index

slice charat

replace

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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