Benchmark: at 500 vs [500] - MeasureThat.net

Script Preparation code:

var k = new Array(10000).fill(Math.random() * 1000).map(e => (Math.random() * 1000));

Tests:

direct access
k[500]
.at
k.at(500)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
direct access
.at

Fastest: N/A

Slowest: N/A

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/18.0.1 Safari/605.1.15

Browser/OS: Safari 18 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
direct access	42463420.0 Ops/sec
.at	42039748.0 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 data and explain what's being tested.

**What is being tested?**

The provided benchmark compares two ways to access an element at index 500 in an array of 10,000 random integers:

1. Direct access: `k[500]`
2. Using the `.at()` method: `k.at(500)`

**Options compared:**

The two options are being tested for their performance differences.

**Pros and Cons of each approach:**

* **Direct access (`k[500]`)**:
	+ Pros:
		- Simple and straightforward
		- Likely to be the most cache-efficient since it's a direct memory access
	+ Cons:
		- May not handle edge cases well (e.g., if the array is not initialized properly)
* **.at() method (`k.at(500)`)**:
	+ Pros:
		- More robust and handles edge cases better
		- Can be useful in scenarios where you need to dynamically determine the index
	+ Cons:
		- May incur a small overhead due to method call and potentially slower cache misses

**Library usage:**

The benchmark uses the `Array.prototype.at()` method, which is a standard JavaScript method introduced in ECMAScript 2022 (ES12). Its purpose is to provide an alternative way to access elements at specific indices in arrays, similar to array indexing with square brackets.

**Special JS feature or syntax:**

There is no special JavaScript feature or syntax being used beyond the `.at()` method. However, it's worth noting that the `fill` method and the use of `Math.random()` for generating random integers are common JavaScript practices.

**Other alternatives:**

If you were to implement a custom implementation for accessing an element at index 500 in an array, some alternatives could include:

* Using an indexing object or a lookup table
* Creating a private helper function within the original function
* Utilizing a data structure like a hash map or a trie

However, these approaches are likely to be less efficient and more complex than using the `.at()` method.

**Benchmark preparation code:**

The provided script preparation code generates an array of 10,000 random integers and assigns them to a variable `k`. The generated array is created on the heap, which can lead to performance differences compared to arrays created on the stack or using other data structures.

Overall, the benchmark provides a simple yet informative comparison between two ways to access elements in an array. By understanding the pros and cons of each approach, developers can make informed decisions about how to optimize their code for performance.

Related benchmarks:

at 500 vs [500] (version: 0)

Comparing performance of: direct access vs .at

Created: 3 years ago by: Guest

Jump to the latest result

direct access

.at

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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