Benchmark: string.at() vs string[0]

Script Preparation code:

let string = 'a'.repeat(3000)

Tests:

string.at()
for (let i = 3000; --i;)var test = string.at()
string[0]
for (let i = 3000; --i;)var test = string[0]

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
string.at()
string[0]

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/130.0.0.0 YaBrowser/24.12.0.0 Safari/537.36

Browser/OS: Yandex Browser 24 on Windows

View result in a separate tab

Test name	Executions per second
string.at()	39692.6 Ops/sec
string[0]	164957.8 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):

LLMs can make mistakes. Check important info.

The benchmark provided compares two different methods of accessing the first character of a string in JavaScript:

1. **`string.at()`**: This method is used to retrieve a character from a string at a specified index. The `at()` method is a relatively newer addition to JavaScript (introduced in ECMAScript 2022) and allows for a more flexible approach to string indexing, including handling negative indices to fetch characters from the end of the string.

2. **`string[0]`**: This method accesses the first character of a string using bracket notation, which has been part of JavaScript since its inception. It is a very straightforward and commonly used way to access elements in arrays and strings.

### Pros and Cons

#### `string.at()`
**Pros:**
- Flexibility: Supports negative indexing, allowing access to characters from the end of the string (e.g., `string.at(-1)` gets the last character).
- Improved readability for beginners, as it clearly indicates that you are accessing a character at a specific index.

**Cons:**
- Potentially slower performance: As indicated by the benchmark results, it has a lower execution rate compared to `string[0]`. This is important in performance-critical applications, especially in loops or large scale operations.
- Not as widely used yet since it is a newer feature; older codebases may not support it.

#### `string[0]`
**Pros:**
- Performance: The benchmark shows that `string[0]` performed better with approximately 1687 executions per second compared to 1499 for `string.at()`, making it a better choice for performance-sensitive code.
- Familiarity: This notation has been used since the early days of JavaScript, making it more recognizable to developers.

**Cons:**
- Limited flexibility: Only allows positive indexing. Negative indexing must be manually calculated.
- Readability may suffer in cases where the intended character position is calculated or derived, making it less clear than `string.at()` could be.

### Other Considerations
The benchmark is fairly straightforward, focusing only on the first character of the string. However, if the string was longer or if more character access methods were included, a wider analysis could be conducted. Considerations such as different lengths of strings, the complexity of the operations, and other environmental factors (like browser optimizations) could influence performance results.

### Alternatives
Other alternatives for accessing string characters could include:
- **Using `String.prototype.slice()`**: This method allows you to extract a segment from the string and can also be used to get the first character, e.g., `string.slice(0, 1)`.
- **Using `String.prototype.substring()`**: Similar to slice, `substring(0, 1)` will also get the first character.
- **Using `String.prototype.charAt()`**: This method returns the character at a specified index as well and has been part of JavaScript for a long time (e.g., `string.charAt(0)`).

Each of these alternatives has its nuances in terms of flexibility and readability but will generally perform similarly to the aforementioned methods depending on the context.

In conclusion, while `string.at()` offers some advantages in terms of usability and flexibility, for accessing the first character of a string, `string[0]` remains the more performant and traditional choice.

Related benchmarks:

string.at() vs string[0] (version: 1)

Comparing performance of: string.at() vs string[0]

Created: one year ago by: Guest

Jump to the latest result

string.at()

string[0]

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one year ago):