Benchmark: charAt(i) vs RegExp

Tests:

charAt()
let pStringDate = '2000-10-07T11:00:34'; let noop = Function.prototype; if (pStringDate.charAt(4) === '-' && pStringDate.charAt(7) === '-' && pStringDate.charAt(10) === 'T' && pStringDate.charAt(13) === ':' && pStringDate.charAt(16) === ':') noop();
RegExp
let pStringDate = '2000-10-07T11:00:34'; let noop = Function.prototype; const pattern = /'(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d:[0-5]\d\.\d+)|(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d:[0-5]\d)|(\d{4}-[01]\d-[0-3]\dT[0-2]\d:[0-5]\d)/g; if (pattern.test(pStringDate)) noop();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
charAt()
RegExp

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/84.0.4147.135 Safari/537.36

Browser/OS: Chrome 84 on Windows

View result in a separate tab

Test name	Executions per second
charAt()	3369921.5 Ops/sec
RegExp	2795986.8 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the JavaScript microbenchmark on MeasureThat.net.

**What is being tested?**

The benchmark compares two approaches to extract the year from a date string: `charAt()` and `RegExp`. The test cases use hardcoded date strings, which are expected to contain specific patterns that match the desired extraction.

**Comparison options:**

1. **charAt()**: This approach uses the built-in `charAt()` method of JavaScript strings to extract individual characters.
2. **RegExp**: This approach uses regular expressions (Regex) to define a pattern that matches the expected date format.

**Pros and cons of each approach:**

* **charAt()**:
	+ Pros: simple, straightforward, and widely supported by most browsers.
	+ Cons: might be slower for more complex patterns or large strings, as it relies on character-by-character iteration.
* **RegExp**:
	+ Pros: can handle complex patterns, is efficient for large strings, and provides flexibility with the `g` flag for global matching.
	+ Cons: requires knowledge of regular expression syntax, which might be unfamiliar to some developers.

**Library usage:**

Neither approach uses any external libraries. However, it's worth noting that JavaScript engines (like V8 in Chrome) often provide optimized implementations of built-in methods like `charAt()` and regex patterns.

**Special JS feature or syntax:**

There is no special JavaScript feature or syntax used in these benchmarks. They focus on a straightforward comparison between two basic approaches to string manipulation.

**Other alternatives:**

If you wanted to use alternative approaches, here are some options:

* **Substring**: Instead of using `charAt()` or regex, you could extract the substring using the `substr()` method.
* **String methods**: Other string methods like `indexOf()`, `lastIndexOf()`, and `slice()` could also be used to extract the desired substring.
* **Date parsing libraries**: For more complex date formatting, you might consider using a dedicated date parsing library like Moment.js or Date-Fns.

Keep in mind that these alternatives would likely change the benchmark results and may not offer significant performance improvements over the `charAt()` and RegExp approaches.

Related benchmarks:

charAt(i) vs RegExp (version: 0)

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Comparing performance of: charAt() vs RegExp

Created: 4 years ago by: Guest

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charAt()

RegExp

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):