Benchmark: Single vs multiple regex replace calls

Script Preparation code:

var str = "Et inventore ut est. Illum dolorem similique odit. Velit necessitatibus unde nostrum sequi ut pariatur suscipit sit magnam. Cum esse sed quod aut id. Recusandae vel commodi."

Tests:

Multiple, regex
str = str.replace(/a/g, '').replace(/e/g,'')
Single, regex
str = str.replace(/a|e/g, '')
Single, group regex
str = str.replace(/[ae]+/g, '')
No regex
str = str.replace('a', '').replace('e','')

Historical Performance Data aggregated from 12 community runs

Desktop Results:

Chrome 12 runs

Single, regex

9.3M/s

No regex

9.2M/s

Single, group regex

8.9M/s

Multiple, regex

6.5M/s

Fastest: Single, regex (1.4x faster)

View exact numbers

✓ Single, regex: 9,349,687 ops/sec
• No regex: 9,193,086 ops/sec
• Single, group regex: 8,904,496 ops/sec
• Multiple, regex: 6,515,676 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Multiple, regex
Single, regex
Single, group regex
No regex

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/137.0.0.0 Safari/537.36

Browser/OS: Chrome 137 on Mac OS X 10.15.7

View result in a separate tab

No regex

10.6M/s

Single, group regex

10.3M/s

Single, regex

10.3M/s

Multiple, regex

8.3M/s

View exact numbers

Test name	Executions per second
✓ No regex	10,595,482 Ops/sec
Single, group regex	10,259,072 Ops/sec
Single, regex	10,252,976 Ops/sec
Multiple, regex	8,312,668 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.

The provided JSON represents a benchmark test case for comparing different approaches to regular expression replacement in JavaScript. The test compares four scenarios:

1. **Multiple regex replace calls**: This involves calling `str.replace()` twice, once with each individual character 'a' and then 'e', which is equivalent to using the `/a/g` and `/e/g` regex patterns.
2. **Single regex**: This involves calling `str.replace()` once with a single regex pattern '/a/' or '/e/', replacing both characters at once.
3. **Single group regex**: This involves calling `str.replace()` once with a regex pattern that uses capturing groups, `[ae]+`, which replaces both 'a' and 'e' characters in one operation.
4. **No regex**: This is the base case where no regular expression replacement is performed.

Let's discuss each approach:

*   **Multiple regex replace calls**:
    *   Pros: More accurate results for each individual character, as both replacements are done separately.
    *   Cons: Requires more iterations and is potentially slower due to the extra function call.
*   **Single regex**: 
    *   Pros: Faster execution since only one `replace()` call is made, reducing overhead from multiple calls.
    *   Cons: May lead to less accurate results if 'a' or 'e' are not unique characters in the input string.
*   **Single group regex**:
    *   Pros: Similar performance benefits as single regex, with the added benefit of handling multiple characters more accurately due to capturing groups.
    *   Cons: Requires more complex regex patterns for multi-character replacements, adding to complexity and potential overhead.
*   **No regex**: 
    *   Pros: Simplest approach with minimal execution overhead, especially beneficial if the replacement strings are short or few.
    *   Cons: Results may be less accurate since no explicit replacement is done.

Other alternatives could involve:

*   Using `str.split()` and then joining the resulting array of characters to remove 'a' and 'e'.
*   Implementing a custom loop through each character in the string, replacing them with an empty string.
*   Utilizing browser-specific features or optimizations that might be available but not captured by this benchmark.

Regarding libraries used or special JavaScript features:

None are explicitly mentioned in the provided JSON. The code relies solely on native JavaScript functions (`replace()`, `split()`).

Single vs multiple regex replace calls (version: 0)

Comparing performance of: `Multiple, regex vs Single, regex vs Single, group regex vs No regex`

Created: 8 years ago by: Registered User

Go to the latest result

Multiple, regex

Single, regex

Single, group regex

No regex

Historical Performance Data aggregated from 12 community runs

Desktop Results:

Chrome 12 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Single vs multiple regex replace calls (version: 0)

Comparing performance of: Multiple, regex vs Single, regex vs Single, group regex vs No regex

Created: 8 years ago by: Registered User

Go to the latest result

Multiple, regex

Single, regex

Single, group regex

No regex

Historical Performance Data aggregated from 12 community runs

Desktop Results:

Chrome 12 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Related benchmarks

Comparing performance of: `Multiple, regex vs Single, regex vs Single, group regex vs No regex`