Benchmark: regex performance with test and exec

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)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
test
exec

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 124 on Android

View result in a separate tab

Test name	Executions per second
test	9748205.0 Ops/sec
exec	8666108.0 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 JSON and explain what's being tested.

**Overview**

The benchmark is testing the performance of regular expression (regex) operations on JavaScript. Specifically, it's comparing the execution speed of two regex methods: `test()` and `exec()`, both applied to a sample HTML string.

**Benchmark Definition JSON**

The JSON defines two test cases:

1. `"test"`: This test case uses the `test()` method to check if a regex pattern matches any part of the input string (`html`). The regex pattern is `/<table\\b[^>]*>/i`, which matches `<table>` elements with any characters (`[^>]`) between the opening and closing tags.
2. `"exec"`: This test case uses the `exec()` method to find the first match of the regex pattern in the input string.

**Options Compared**

The benchmark is comparing the performance of two approaches:

1. **`test()`**: This method attempts to match the entire input string against the regex pattern, returning a boolean result indicating whether there's a match.
2. **`exec()`**: This method scans the input string for matches, returning an object with information about the match if found.

**Pros and Cons**

**`test()`**:

Pros:

* Simple and straightforward implementation
* Fast execution due to the simple matching process

Cons:

* Can be slower for larger inputs due to the exhaustive search
* May cause performance issues in browsers that don't support `test()` (e.g., older versions of Internet Explorer)

**`exec()`**:

Pros:

* Faster execution for larger inputs due to the incremental scanning approach
* More efficient use of CPU resources

Cons:

* Requires an additional function call overhead (creating a match object and dealing with potential errors)
* May be slower for smaller inputs due to the overhead of searching for matches

**Library Usage**

Neither `test()` nor `exec()` rely on specific libraries. However, these methods are built-in JavaScript functions, which means that the benchmark is testing the performance of the JavaScript engine's regex implementation.

**Special JS Features/Syntax**

There are no special JS features or syntax mentioned in this benchmark. The test cases use standard JavaScript programming constructs and regex patterns.

**Other Alternatives**

If you want to explore other approaches for benchmarking regex performance, consider:

1. **`RegExp.prototype.test()` vs. `RegExp.prototype.exec()`**: This is similar to the current benchmark, but with an emphasis on comparing different versions or implementations of these methods.
2. **Regex optimization techniques**: Explore optimizing regex patterns for better performance, such as using lazy matching, anchoring, or character classes.
3. **Other JavaScript engines**: Test your benchmarks against other JavaScript engines, like V8 (used by Node.js), SpiderMonkey (used by Firefox), or SquirrelFish (used by Safari).

Feel free to ask if you have any further questions!

Related benchmarks:

regex performance with test and exec (version: 0)

Comparing performance of: test vs exec

Created: 4 years ago by: Guest

Jump to the latest result

test

exec

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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