Benchmark: `array[i]` vs `array.at(i)`

Script Preparation code:

var array = [1,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3,2,3]
var N = array.length

Tests:

array[i]
let sum = 0 for (let i = 0; i < N; i++) sum += array[i]
array.at(i)
let sum = 0 for (let i = 0; i < N; i++) sum += array.at(i)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

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

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/126.0.0.0 Safari/537.36

Browser/OS: Chrome 126 on Windows

View result in a separate tab

Test name	Executions per second
array[i]	262712.5 Ops/sec
array.at(i)	259925.8 Ops/sec

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the benchmark.

**What is being tested?**

MeasureThat.net is comparing two approaches for accessing elements in an array: `array[i]` and `array.at(i)`. The test case uses an array of 30 elements, where each element appears multiple times.

**Options compared:**

1. **`array[i]`:** This approach uses the traditional array indexing syntax, where you specify the index of the element you want to access using square brackets (`[]`). For example, `array[0]`, `array[10]`, etc.
2. **`array.at(i)`:** This approach uses the `at()` method, which is a relatively new feature introduced in ECMAScript 2019 (ES2020). The `at()` method returns the element at the specified index, and also provides additional features like handling out-of-bounds indices and more.

**Pros and Cons:**

1. **`array[i]`:**
	* Pros:
		+ Widely supported in older browsers and environments.
		+ Generally faster execution speed.
	* Cons:
		+ More code to write, as you need to specify the index explicitly.
		+ Can lead to errors if the array length changes unexpectedly.
2. **`array.at(i)`:**
	* Pros:
		+ More concise and readable code.
		+ Handles out-of-bounds indices more elegantly, reducing errors.
		+ May be faster in newer browsers and environments.
	* Cons:
		+ Less widely supported in older browsers and environments (not yet adopted by all major browsers).
		+ May have performance overhead due to the additional method call.

**Library used:**

In this test case, there is no specific library being used. The array data and the benchmarking logic are defined directly in the JavaScript code.

**Special JS feature or syntax:**

The `at()` method is a relatively new feature introduced in ECMAScript 2019 (ES2020). It was added to provide a more modern and expressive way of accessing elements in arrays, while also handling edge cases like out-of-bounds indices.

**Other alternatives:**

If you were to use alternative approaches for accessing array elements, some options might include:

* Using `Array.prototype.indexOf()` or `Array.prototype.findIndex()` to find the index of an element, then using indexing (`array[index]`) to access it.
* Using a library like Lodash, which provides utility functions for working with arrays and other data structures.

However, in this specific test case, the comparison is between `array[i]` and `array.at(i)`, so these alternatives are not relevant.

Related benchmarks:

`array[i]` vs `array.at(i)` (version: 9)

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

Created: 2 years ago by: Registered User

Jump to the latest result

array[i]

array.at(i)

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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