Benchmark: charCodeAt vs codePointAt actually using unicode chars

Script Preparation code:

var str = "some str😀ing heresome string he😀resome string heresome st😀ring heresome str😀ing heresome 😀string heresome string heres😀ome string heresome string heresome stri😀g heresome string heresome string heresome str😀ing heresome string heresome string heresome string her😀😀😀😀esome string heresome string here😀some string here"

Tests:

charCodeAt
str.charCodeAt(20)
codePointAt
str.codePointAt(20)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
charCodeAt
codePointAt

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one year ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Windows

View result in a separate tab

Test name	Executions per second
charCodeAt	104246848.0 Ops/sec
codePointAt	106174448.0 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll break down the provided benchmark and explain what's being tested, compared options, pros and cons, and other considerations.

**Benchmark Definition**

The benchmark measures the performance difference between two JavaScript methods: `charCodeAt` and `codePointAt`. Both methods are used to access Unicode code points in a string. The test uses a specific string with various Unicode characters to exercise these methods.

**Options Compared**

There are two main options being compared:

1. **charCodeAt**: This method returns the Unicode code point value of a one-character sequence within the string. It's a legacy method that has been around since the early days of JavaScript.
2. **codePointAt**: This method returns the Unicode code point value at a specified index in the string. It was introduced in ECMAScript 2019 (ES2020) as a more modern alternative to `charCodeAt`.

**Pros and Cons**

* **charCodeAt**:
	+ Pros: Wide compatibility, works in older browsers and environments.
	+ Cons: Limited functionality, only returns code point values for single characters, doesn't handle Unicode normalization or surrogate pairs.
* **codePointAt**:
	+ Pros: More modern, accurate, and efficient, handles Unicode normalization and surrogate pairs.
	+ Cons: Requires a minimum JavaScript engine that supports ES2020 (e.g., Chrome 126+, Firefox 96+, Node.js 14+), might not work in older browsers or environments.

**Library Usage**

There is no explicit library usage mentioned in the benchmark definition. However, it's likely that the test assumes the use of a modern JavaScript engine with built-in support for `codePointAt`. If an older browser or environment is used, `charCodeAt` will be executed instead.

**Special JS Feature/Syntax**

The benchmark uses Unicode characters (e.g., `😀`) to exercise both methods. While this might seem like a specialized feature, it's actually a common practice in JavaScript benchmarks to use Unicode characters to test string manipulation and encoding/decoding logic.

**Other Considerations**

When designing benchmarks like this one, consider the following:

* **Relevance**: Ensure that the benchmark measures something meaningful and representative of real-world scenarios.
* **Coverage**: Use a diverse set of input data to cover various edge cases and normal usage patterns.
* **Comparison**: Compare relevant metrics (e.g., execution speed) rather than just comparing code snippets or methods.
* **Environment**: Consider the specific environments where your benchmark will run, including older browsers, mobile devices, or other platforms.

**Alternative Benchmarks**

Some alternative benchmarks might focus on:

* Other string manipulation methods, such as `substr`, `slice`, or `indexOf`.
* Unicode normalization and surrogate pairs handling.
* Encoding/decoding logic using different algorithms (e.g., UTF-8, UTF-16).
* Specialized use cases, like working with non-ASCII characters in languages other than English.

Keep in mind that benchmarking JavaScript code is complex, and it's essential to consider the specific requirements of your project or application when designing and executing benchmarks.

Related benchmarks:

charCodeAt vs codePointAt actually using unicode chars (version: 0)

Comparing performance of: charCodeAt vs codePointAt

Created: 4 years ago by: Guest

Jump to the latest result

charCodeAt

codePointAt

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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