Benchmark: Trim regex string

Script Preparation code:

var pat = "/^http.?:\/\/.+\.com/";

Tests:

regex replace
pat.replace(/^\/|\/$/g, "");
string substring
pat.substring(1, pat.length - 1);
string slice
pat.slice(1, -1)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
regex replace
string substring
string slice

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Linux

View result in a separate tab

Test name	Executions per second
regex replace	1106691.2 Ops/sec
string substring	1847921.6 Ops/sec
string slice	3492277.2 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 benchmark and explain what's being tested.

**Benchmark Overview**

The benchmark is designed to measure the performance of three different approaches for processing a regular expression (regex) string:

1. `regex.replace()` (case 1)
2. `substring()` method (case 2)
3. `slice()` method (case 3)

**Test Cases**

Each test case consists of a JavaScript code snippet that prepares a regex pattern and then applies the respective approach to process it.

* Case 1: `pat.replace(/^\\/|\\/$/g, "");` - This code uses the `replace()` method to remove the first and last characters from the pattern.
* Case 2: `pat.substring(1, pat.length - 1)` - This code uses the `substring()` method to extract a substring from the pattern, starting from index 1 and ending at the second-to-last character.
* Case 3: `pat.slice(1, -1)` - This code uses the `slice()` method to create a new string that includes all characters except the first and last ones.

**Library Used**

None of the test cases explicitly use any external libraries. The regex pattern is defined directly in the script preparation code.

**Special JS Features or Syntax**

None of the test cases utilize any special JavaScript features or syntax beyond standard ES6 JavaScript (which `substring()` and `slice()` are part of).

**Approach Comparison**

The three approaches differ in their efficiency, readability, and potential side effects:

* **`regex.replace()`**: This approach is generally more efficient and concise, as it leverages the optimized regex engine. However, it can be slower due to the overhead of regular expression compilation.
* **`substring()`**: This method is less efficient than `replace()`, but more readable. It creates a new substring object, which can be memory-intensive for large strings.
* **`slice()`**: Similar to `substring()`, this method creates a new string and can be slower due to the overhead of creating a new string.

**Pros and Cons**

| Approach | Pros | Cons |
| --- | --- | --- |
| `regex.replace()` | Efficient, concise, optimized for regex operations | Potential overhead due to compilation |
| `substring()` | Readable, less memory-intensive | Less efficient than `replace()`, creates a new substring object |
| `slice()` | More readable, avoids creating a new string like `substring()` | Less efficient, creates a new string |

**Other Alternatives**

Some alternative approaches could be:

* Using a different regex pattern or optimization technique
* Utilizing native WebAssembly (WASM) performance features if available
* Implementing custom optimized algorithms for specific use cases

Keep in mind that the choice of approach depends on the specific requirements and constraints of your project.

**Benchmark Results**

The provided benchmark results show the execution rate per second for each test case across multiple devices. The results suggest that:

* `regex.replace()` is generally the fastest
* `slice()` is slower than both `replace()` and `substring()`, likely due to its overhead in creating a new string
* `substring()` falls somewhere in between, offering a balance of efficiency and readability

These findings should help you choose the best approach for your specific use case.

Related benchmarks:

Trim regex string (version: 0)

Comparing performance of: regex replace vs string substring vs string slice

Created: 2 years ago by: Guest

Jump to the latest result

regex replace

string substring

string slice

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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