Benchmark: Get by index - MeasureThat.net

Script Preparation code:

var arr = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20];

Tests:

First item
var res = arr[0];
Last item
var res = arr[19];
Other item
var res = arr[5];

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
First item
Last item
Other item

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/78.0.3904.108 Safari/537.36

Browser/OS: Chrome 78 on Linux

View result in a separate tab

Test name	Executions per second
First item	6867332.5 Ops/sec
Last item	5581348.5 Ops/sec
Other item	4945746.5 Ops/sec

Autogenerated LLM Summary (model gemma2:9b, generated one month ago):

LLMs can make mistakes. Check important info.

This benchmark tests the performance of accessing elements in an array by their index in JavaScript.

**What's being tested:**  The provided JSON defines three test cases, each retrieving a different element from an array:

* **"First item":** Retrieves the first element (`arr[0]`)
* **"Last item":** Retrieves the last element (`arr[19]`)
* **"Other item":** Retrieves a middle element (`arr[5]`)

**Options Compared:** The only "option" being compared is how JavaScript handles array indexing. There are no different libraries or approaches presented in these test cases. All three tests simply use basic array syntax to access elements.

**Pros/Cons:**

* **Simplicity:**  Accessing array elements by index is a fundamental operation in programming, and this benchmark highlights its straightforward nature in JavaScript.
* **Benchmark Focus:** The benchmark focuses solely on the array indexing operation itself, isolating it from other potential performance bottlenecks in a larger program.

**Other Considerations:**

* **Array Size:** The size of the array (20 elements) is relatively small.  The results might change significantly with much larger arrays.
* **Element Type:** All test cases retrieve numerical values (`number` type). Accessing complex objects or strings from an array could introduce different performance characteristics.
* **Caching Effects:** JavaScript engines may optimize repeated access to the same array elements, potentially impacting the benchmark's results.

**Alternatives:**

While this benchmark focuses on basic indexing, other potential tests could explore:

* **Sparse Arrays:** Accessing elements in arrays with many gaps (sparse arrays) could reveal performance differences due to memory allocation.
* **Dynamic Array Resizing:** Measuring performance when the array size changes frequently would highlight how JavaScript handles these operations.
* **Library Comparisons:** Comparing indexing performance using libraries like Lodash or Underscore, which might offer optimized methods for array manipulation.

Related benchmarks:

Get by index (version: 0)

Comparing performance of: First item vs Last item vs Other item

Created: 4 years ago by: Registered User

Jump to the latest result

First item

Last item

Other item

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gemma2:9b, generated one month ago):