Benchmark: array[] vs array.at()

Script Preparation code:

var array = [0, 1, 2, 3]

Tests:

array[0]
const a = array[0]
array.at(0)
const b = array.at(0)

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

array.at(0)

159.8M/s

array[0]

157.8M/s

View exact numbers

✓ array.at(0): 159,828,992 ops/sec
• array[0]: 157,786,112 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 11 months ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/139.0.0.0 Safari/537.36 Edg/139.0.0.0

Browser/OS: Chrome 139 on Windows

View result in a separate tab

array.at(0)

80.1M/s

array[0]

43.4M/s

View exact numbers

Test name	Executions per second
✓ array.at(0)	80,050,528 Ops/sec
array[0]	43,389,528 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's break down the provided benchmark and explain what's being tested, along with the pros and cons of each approach.

**Benchmark Overview**

The benchmark is designed to compare the performance of accessing elements in an array using two different syntaxes: `array[0]` and `array.at(0)`. The goal is to determine which method is faster and more efficient.

**What's being tested?**

* Two options are compared:
	+ `array[0]`: a traditional, index-based access method.
	+ `array.at(0)`: an optional chaining method introduced in JavaScript (ECMAScript 2020) that allows accessing array elements using dot notation.
* The benchmark uses two individual test cases: one for each syntax.

**Pros and Cons of each approach**

### `array[0]`

Pros:

* Widely supported across most browsers and JavaScript implementations.
* Familiar syntax for many developers.
* Typically faster execution since it directly accesses the element without any additional overhead.

Cons:

* May not be as efficient in modern browsers that have optimized array access methods (e.g., Chrome).

### `array.at(0)`

Pros:

* More concise and readable syntax, especially when working with large arrays or nested objects.
* Can be more expressive, allowing for better error handling and code organization.

Cons:

* May incur additional overhead due to the optional chaining mechanism:
	+ In older browsers that don't support this syntax, it may result in slower execution or errors.
	+ Modern browsers might use internal optimizations, which could affect performance.
	+ Additional parsing and validation steps during runtime can slow down access times.

**Library/Feature**

In this benchmark, no specific library is used. However, the `array.at(0)` method relies on the optional chaining feature introduced in ECMAScript 2020. This feature allows accessing nested properties using dot notation, which has its own set of implications and considerations.

**Special JS Feature/Syntax**

The benchmark uses a special JavaScript syntax, `array.at(0)`, which is a relatively recent addition to the language (introduced in ECMAScript 2020). While it's gaining popularity, its adoption rate might be lower compared to more established methods like `array[0]`. This highlights the importance of considering browser support and compatibility when writing benchmarks or using new syntaxes.

**Alternatives**

If you're looking for alternatives to this benchmark or want to explore other performance comparison scenarios:

1. **Array indexing vs. array slicing**: Compare the performance of accessing elements in an array using `array[0]`, `array.slice(0, 1)`, or similar methods.
2. **Object property access vs. bracket notation**: Investigate the differences between accessing object properties using dot notation (`obj.prop`) and bracket notation (`obj['prop']`).
3. **Array iteration vs. for...of loop**: Compare the performance of iterating over an array using traditional `for` loops versus modern `for...of` loops.

Keep in mind that these alternative scenarios can help you better understand the nuances of JavaScript performance, browser support, and code optimization techniques.

array[] vs array.at() (version: 0)

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

Created: 2 years ago by: Guest

Go to the latest result

array[0]

array.at(0)

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

array[] vs array.at() (version: 0)

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

Created: 2 years ago by: Guest

Go to the latest result

array[0]

array.at(0)

Historical Performance Data aggregated from 8 community runs

Desktop Results:

Chrome 8 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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