Benchmark: string.charCodeAt(index) vs string[index].charCodeAt()

Script Preparation code:

var str = "some string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string heresome string here"

Tests:

charCodeAt(0)
str.charCodeAt(0)
charCodeAt(300)
str.charCodeAt(300)
[0].charCodeAt()
str[0].charCodeAt()
[300].charCodeAt()
str[300].charCodeAt()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
charCodeAt(0)
charCodeAt(300)
[0].charCodeAt()
[300].charCodeAt()

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.5 Safari/605.1.15

Browser/OS: Safari 17 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
charCodeAt(0)	31846490.0 Ops/sec
charCodeAt(300)	31957028.0 Ops/sec
[0].charCodeAt()	24080684.0 Ops/sec
[300].charCodeAt()	23939364.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the world of JavaScript microbenchmarks!

**Benchmark Definition JSON**

The provided JSON defines two benchmark scenarios:

1. **`string.charCodeAt(index) vs string[index].charCodeAt()`**: This benchmark compares the performance of using `charCodeAt()` on a string by accessing its index directly (`str[index]`) versus using the indexed property (`str.charCodeAt()`) to access the character at that index.
2. The subsequent test cases in the `Individual Test Cases` array measure the execution time for each of these scenarios, testing both the first and last characters of the string.

**Options being compared**

The options being compared are:

* **`charCodeAt()`**: A method on strings that returns the Unicode code point at a specific index.
* **`string[index]`**: Direct access to the character at an index in a string (which is equivalent to `str.charCodeAt(index)` but less efficient).

**Pros and Cons**

Using `charCodeAt()`: Pros:

* More readable and maintainable, as it explicitly conveys its purpose.
* Less prone to off-by-one errors or indexing issues.

Cons:

* May incur additional overhead due to method calls and checks for null or undefined inputs.

Direct Access (`string[index]`): Pros:

* Typically faster, as it avoids the overhead of a method call and doesn't require explicit handling of potential errors.
* Often considered more efficient in terms of CPU cycles.

Cons:

* Less readable and maintainable, as its intent is not immediately clear.
* More prone to off-by-one errors or indexing issues if not used carefully.

**Library: `String.prototype.charCodeAt()`**

The `charCodeAt()` method is a part of the String prototype in JavaScript. It's a standard built-in method that returns the Unicode code point at the specified index, and its purpose is to access the character(s) at a specific position within a string.

**Special JS Feature/Syntax: None mentioned**

There are no special JS features or syntaxes used in this benchmark.

**Other Alternatives**

If you want to measure other aspects of JavaScript performance, here are some potential alternatives:

* Benchmarking the performance of `slice()` vs. array methods (e.g., `Array.prototype.slice()`, `Array.prototype.subarray()`)
* Measuring the execution time for iterating over arrays using traditional loops vs. modern methods like `for...of` or `forEach()`
* Evaluating the performance impact of different data structures, such as arrays vs. objects or sets
* Comparing the efficiency of various optimization techniques, like memoization or caching

Related benchmarks:

string.charCodeAt(index) vs string[index].charCodeAt() (version: 0)

Comparing performance of: charCodeAt(0) vs charCodeAt(300) vs [0].charCodeAt() vs [300].charCodeAt()

Created: 2 years ago by: Guest

Jump to the latest result

charCodeAt(0)

charCodeAt(300)

[0].charCodeAt()

[300].charCodeAt()

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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