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startsWith vs charCodeAt
(version: 0)
Comparing performance of:
startsWith vs charCodeAt
Created:
2 years ago
by:
Guest
Jump to the latest result
Script Preparation code:
str = "hello world"
Tests:
startsWith
str.startsWith('he') === true
charCodeAt
str.charCodeAt(0) === 104
Rendered benchmark preparation results:
Suite status:
<idle, ready to run>
Run tests (2)
Previous results
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Test case name
Result
startsWith
charCodeAt
Fastest:
N/A
Slowest:
N/A
Latest run results:
Run details:
(Test run date:
19 days ago
)
User agent:
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/146.0.0.0 Safari/537.36
Browser/OS:
Chrome 146 on Mac OS X 10.15.7
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<iframe src="https://measurethat.net/Embed?id=627838" width="100%" height="500px"></iframe>
Test name
Executions per second
startsWith
239979024.0 Ops/sec
charCodeAt
272865824.0 Ops/sec
Autogenerated LLM Summary
(model
llama3.2:3b
, generated one year ago):
I'd be happy to explain what's being tested in this JavaScript benchmark. **Benchmark Overview** The benchmark is designed to compare the performance of two different approaches: `str.startsWith('he')` and `str.charCodeAt(0) === 104`. The goal is to determine which approach is faster on a variety of devices, including iPhones. **Options Compared** Two options are being compared: 1. **`str.startsWith('he')`**: This method checks if the string `str` starts with the characters `'he'`. 2. **`str.charCodeAt(0) === 104`**: This method converts the first character of the string `str` to its corresponding ASCII code (104 for 'h') and then compares it to 104. **Pros and Cons** * **`str.startsWith('he')`**: * Pros: Simple, straightforward, and easy to understand. It's a common pattern used in many applications. * Cons: May be slower due to the string search operation. * **`str.charCodeAt(0) === 104`**: * Pros: Can be faster because it uses an ASCII code lookup table, which is optimized for performance. * Cons: Requires understanding of ASCII codes and may not work as expected with non-ASCII characters. **Library and Purpose** In this benchmark, the `charCodeAt()` method is part of the JavaScript standard library, which provides a way to access the Unicode code point for each character in a string. This method is useful when you need to perform operations based on the ASCII or Unicode value of a character. **Special JS Feature or Syntax** There doesn't appear to be any special JavaScript feature or syntax being used in this benchmark that requires deep knowledge of JavaScript. **Other Alternatives** If you want to create similar benchmarks, you can use tools like Benchmark.js, which provides a simple way to write and run benchmarks. You can also consider using libraries like BenchmarkSuite or Jest, which offer more advanced features for writing and running benchmarks. In summary, this benchmark is designed to compare the performance of two different approaches: `str.startsWith('he')` and `str.charCodeAt(0) === 104`. The `charCodeAt()` method uses an ASCII code lookup table, making it potentially faster than the string search operation used in `startsWith()`.
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