Benchmark: regex performance

Script Preparation code:

var html = "<p>A</p><table><tr><td>1</td><td>2</td></tr></table><p>B</p>";

Tests:

test
/<table\b[^>]*>/i.test(html)
exec
/<table\b[^>]*>/i.exec(html)
match
html.match(/<table\b[^>]*>/i)
indexOf
html.toLowerCase().indexOf('<table')

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
test
exec
match
indexOf

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36

Browser/OS: Chrome 120 on Windows

View result in a separate tab

Test name	Executions per second
test	6746597.5 Ops/sec
exec	5783589.5 Ops/sec
match	5416325.0 Ops/sec
indexOf	11072875.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark, where users can compare the performance of different approaches to test regular expressions in a specific HTML string.

**Script Preparation Code**

The script preparation code is used to create the input HTML string:

```javascript
var html = "<p>A</p><table><tr><td>1</td><td>2</td></tr></table><p>B</p>";
```

This string contains a table with some text, which will be used as the test data for the regular expression tests.

**Html Preparation Code**

The HTML preparation code is empty, indicating that no additional HTML strings need to be generated for the benchmark.

**Individual Test Cases**

There are four individual test cases:

1. **test**: `/<table\\b[^>]*>/i.test(html)`
	* This test uses the `test()` method of the regular expression object.
	* It tests whether the input string matches the pattern, with the `i` flag for case-insensitive matching.
2. **exec**: `/<table\\b[^>]*>/i.exec(html)`
	* This test uses the `exec()` method of the regular expression object.
	* It attempts to find the first match of the pattern in the input string and returns a result.
3. **match**: `html.match(/<table\\b[^>]*>/i)`
	* This test uses the `match()` method of the String object.
	* It searches for all occurrences of the pattern in the input string and returns an array of matches.
4. **indexOf**: `html.toLowerCase().indexOf('<table')`
	* This test uses the `toLowerCase()` method to convert the input string to lowercase and then uses the `indexOf()` method to find the index of the first occurrence of '<table'.

**Libraries and Features**

None of these tests use any external libraries or special JavaScript features.

**Pros and Cons of Different Approaches**

1. **test()**: This approach is simple and efficient, as it only requires a single pass through the input string.
	* Pros: Fast and lightweight.
	* Cons: May not be suitable for large input strings or complex patterns.
2. **exec()**: This approach can return more information about the match, such as the start position and the matched text.
	* Pros: Can provide more detailed results than `test()`.
	* Cons: May be slower due to the additional overhead of returning a result object.
3. **match()**: This approach returns an array of all matches in the input string, which can be useful for certain use cases.
	* Pros: Can return multiple matches and is suitable for searching large input strings.
	* Cons: May be slower than `test()` due to the additional overhead of creating an array.
4. **indexOf()**: This approach uses a simpler search algorithm that only searches for the first occurrence of the pattern.
	* Pros: Fast and lightweight, but may not be suitable for finding all occurrences.
	* Cons: May not be suitable for complex patterns or large input strings.

**Other Alternatives**

1. `regex.test()` vs. `test()`: These two methods are similar, but `regex.test()` is a static method that can be called without creating an object.
2. `String.prototype.match()` vs. `match()`: Both methods return an array of matches, but `String.prototype.match()` uses the `g` flag for global matching, which may affect performance.
3. `indexOf()` vs. `search()`: While both methods search for a substring in a string, `indexOf()` is more general and can be used to search for any character sequence, whereas `search()` only searches for a single substring.

Overall, the choice of approach depends on the specific requirements of the use case, such as performance, simplicity, or the need to return detailed results.

Related benchmarks:

regex performance (version: 0)

Comparing performance of: test vs exec vs match vs indexOf

Created: 5 years ago by: Guest

Jump to the latest result

test

exec

match

indexOf

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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