Benchmark: split index 0 vs regex replace

Tests:

replace regex
'20240910T13:45:22.030Z'.replace(/T.*$/, '');
split index 0
'20240910T13:45:22.030Z'.split("T")[0];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
replace regex
split index 0

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the benchmark and explain what is being tested.

**Benchmark Definition**

The benchmark defines two test cases:

1. `split index 0`: This test case measures the performance of using an array index to split a string. The script preparation code for this test case is empty, which means that only the JavaScript code itself is being measured.
2. `replace regex`: This test case measures the performance of using regular expressions (regex) to replace a part of a string. The benchmark definition includes a sample string `'20240910T13:45:22.030Z'` and the regex pattern `/T.*$/`. The script preparation code for this test case is also empty.

**Options compared**

The benchmark is comparing two approaches:

1. **Array indexing**: Using an array index to split a string, as in `split(index)[0]`.
2. **Regular expressions**: Using regex to replace a part of a string, as in `replace(regex pattern, replacement)`.

**Pros and cons**

**Array indexing:**

Pros:

* Simple and straightforward
* Can be faster for simple cases

Cons:

* May not handle edge cases (e.g., null or undefined input)
* May not be as efficient as regex for complex patterns

**Regular expressions:**

Pros:

* Flexible and powerful for matching complex patterns
* Can handle edge cases

Cons:

* Can be slower than array indexing for simple cases
* More complex to use, especially for beginners

**Library usage**

There is no explicit library mentioned in the benchmark definition. However, it's possible that a JavaScript engine or interpreter (e.g., V8) might be using an internal implementation of regex under the hood.

**Special JS features or syntax**

There are no special JavaScript features or syntax used in this benchmark. Both test cases use standard JavaScript concepts and built-in functions.

**Other alternatives**

If you're interested in exploring alternative approaches, here are a few examples:

1. **String manipulation functions**: Instead of using array indexing or regex, you could use built-in string manipulation functions like `substring()` or `replace()`.
2. **Native performance APIs**: Some JavaScript engines provide native performance APIs that allow you to optimize your code for specific tasks. For example, in V8, you can use the `fastString` API to improve string operations.
3. **Native libraries**: Depending on the platform and browser, there might be native libraries available that provide optimized implementations of string manipulation or regex functions.

Overall, this benchmark is designed to compare the performance of two common JavaScript approaches: array indexing and regular expressions. By running this benchmark, users can gain insights into which approach is faster for their specific use cases.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/128.0.0.0 Safari/537.36

Browser/OS: Chrome 128 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
replace regex	23512158.0 Ops/sec
split index 0	45137628.0 Ops/sec

Related benchmarks:

split index 0 vs regex replace (version: 0)

Comparing performance of: replace regex vs split index 0

Created: 2 months ago by: Guest

Jump to the latest result

replace regex

split index 0

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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