Benchmark: array element access

Script Preparation code:

arr = [1, 2, 3]

Tests:

destructure 0
const [a] = arr
destructure 1
const [,a] = arr
bracket 00
const a = arr[0]
bracket 1
const a = arr[1]
at 0
const a = arr.at(0)
at 1
const a = arr.at(1)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
destructure 0
destructure 1
bracket 00
bracket 1
at 0
at 1

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Measuring the performance of different ways to access an array element is a common benchmark, and Measured That.net provides a useful platform for comparing various approaches.

**Benchmark Goal:**
The goal of this benchmark is to measure the performance difference between various methods of accessing an array element, which can help developers understand how their code will perform in different scenarios.

**Test Cases:**

1. **Destructuring**: The first test case uses destructuring assignment (`const [a] = arr` and `const [, a] = arr`) to access the first element of the array.
2. **Bracket Notation**: The second test case uses bracket notation (`arr[0]` and `arr[1]`) to access the first two elements of the array.
3. **Array.prototype.at()**: The third and fourth test cases use the `at()` method (introduced in ECMAScript 2019) to access the first two elements of the array.

**Options Compared:**

* Destructuring assignment (`const [a] = arr` and `const [, a] = arr`)
* Bracket notation (`arr[0]` and `arr[1]`)
* Array.prototype.at() (`arr.at(0)` and `arr.at(1)`)
* Other methods (not shown in the provided benchmark)

**Pros and Cons:**

* **Destructuring assignment**: Pros:
	+ Can be more concise and expressive than other methods.
	+ Less error-prone, as it allows for early error detection if the array is empty or has fewer elements than expected.
	+ Can be faster, as it avoids the overhead of a function call. Cons:
	+ May require modern JavaScript versions that support destructuring assignment (ECMAScript 2015 and later).
* **Bracket notation**: Pros:
	+ Widely supported across browsers and environments.
	+ Does not require modern JavaScript versions.
	Cons:
	+ Can be more verbose than other methods.
	+ May lead to errors if the array index is incorrect or out of bounds.
* **Array.prototype.at()**: Pros:
	+ Introduced in ECMAScript 2019, so it's a relatively new method that can provide faster performance.
	+ Allows for optional chaining (e.g., `arr.at(0)?.doSomething()`), which can be useful in some scenarios. Cons:
	+ Requires modern JavaScript versions to work.
	+ May not be supported in older browsers or environments.

**Library:**
None explicitly mentioned in the benchmark definition.

**Special JS Feature/Syntax:**
The benchmark uses ECMAScript 2019's `at()` method, which is a relatively new feature. The test cases also use modern JavaScript syntax (e.g., arrow functions, destructuring assignment).

**Other Alternatives:**
In addition to the methods mentioned in the benchmark, other alternatives for accessing array elements might include:

* For loops
* While loops
* Using `Array.prototype.forEach()` or `Array.prototype.map()`
* Using a function that takes an array as an argument

Keep in mind that these alternative approaches may have different performance characteristics and use cases compared to the methods mentioned in the benchmark.

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.1 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
destructure 0	7860518.0 Ops/sec
destructure 1	7725634.5 Ops/sec
bracket 00	7918839.0 Ops/sec
bracket 1	8146281.5 Ops/sec
at 0	7820230.0 Ops/sec
at 1	7792594.0 Ops/sec

Related benchmarks:

array element access (version: 0)

Try different ways of accessing an array element

Comparing performance of: destructure 0 vs destructure 1 vs bracket 00 vs bracket 1 vs at 0 vs at 1

Created: one year ago by: Registered User

Jump to the latest result

destructure 0

destructure 1

bracket 00

bracket 1

at 0

at 1

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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