Benchmark: Regex vs split 2

Script Preparation code:

var str = 'image/png';

Tests:

Regex
str.split(/\//g);
Split and Join
str.split('/')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Regex
Split and Join

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 3 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/92.0.4515.131 Safari/537.36

Browser/OS: Chrome 92 on Windows

View result in a separate tab

Test name	Executions per second
Regex	3946085.2 Ops/sec
Split and Join	3565139.5 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to explain what's tested in this JavaScript microbenchmark on MeasureThat.net.

**Overview**

The benchmark tests two approaches for splitting a string: using a regular expression (`Regex`) versus simply splitting the string at each forward slash (`Split and Join`).

**Test Cases**

There are two individual test cases:

1. **Regex**: The script uses the `str.split(/\\//g);` statement, which attempts to split the input string `str` into substrings using a regular expression. The `/\\//g` pattern matches each forward slash (`/`) character in the string, regardless of whether it's escaped with a backslash (`\`). The `g` flag at the end of the pattern ensures that all matches are found (not just the first one).
2. **Split and Join**: The script uses the `str.split('/')` statement, which simply splits the input string `str` into substrings using each forward slash (`/`) character as a delimiter.

**Options Compared**

The two approaches differ in how they handle escaped forward slashes:

* **Regex**: In this approach, the regular expression engine will not escape the backslashes within the pattern. This means that if the input string contains an unescaped forward slash followed by another forward slash (e.g., `image/`), it will still be matched as a single delimiter.
* **Split and Join**: In contrast, this approach does not perform any regular expression processing at all; it simply treats each forward slash (`/`) character as a separator.

**Pros and Cons**

Here are some pros and cons of each approach:

* **Regex**:
	+ Pros: Can handle escaped delimiters more robustly.
	+ Cons: May be slower due to the complexity of regular expression processing.
* **Split and Join**:
	+ Pros: Typically faster, as it doesn't involve regular expression processing.
	+ Cons: Will not handle escaped delimiters correctly.

**Library**

There is no explicit library mentioned in this benchmark. However, the `str.split()` method is a built-in JavaScript method that operates on strings.

**Special JS Features/Syntax**

This benchmark does not use any special JavaScript features or syntax beyond the standard `split()` and regular expression operators.

**Alternatives**

If you're interested in exploring alternative approaches for splitting strings, consider the following:

* **String.prototype.replace()**: Instead of using `split()`, you can use `replace()` with a callback function to split the string.
* **String.prototype.splitter()**: Some JavaScript engines (like V8) offer a built-in `splitter()` method that allows for more flexible string splitting.

Keep in mind that these alternatives may not provide significant performance benefits over the standard `split()` method, and their usage can depend on specific use cases and requirements.

Related benchmarks:

Regex vs split 2 (version: 0)

Comparing performance of: Regex vs Split and Join

Created: 3 years ago by: Guest

Jump to the latest result

Regex

Split and Join

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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