Benchmark: Array sequential access

Script Preparation code:

var arr = Array.from({length: 100000})

Tests:

pop
let a = 0 while (arr.length) { a = arr.pop() }
shift
let a = 0 while (arr.length) { a = arr.shift() }
i
let a = 0 let i = 0 while (i < arr.length) { a = arr[i] i++ }
reversed pop
let a = 0 arr.reverse() while (arr.length) { a = arr.pop() }
cached i
let a = 0 let i = 0 const len = arr.length while (i < len) { a = arr[i] i++ }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
pop
shift
i
reversed pop
cached i

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/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Browser/OS: Chrome 125 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
pop	26046796.0 Ops/sec
shift	25793928.0 Ops/sec
i	26179348.0 Ops/sec
reversed pop	13485532.0 Ops/sec
cached i	26270360.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Overview**

The benchmark is designed to measure the performance of sequential array access operations in JavaScript. It creates an array with 100,000 elements and then executes various microbenchmarks that manipulate this array using different approaches.

**Options Compared**

There are five test cases:

1. `pop`: Removes an element from the end of the array.
2. `shift`: Removes an element from the beginning of the array.
3. `i`: Iterates through the array elements using a traditional `while` loop with indexing (`arr[i]`).
4. `cached i`: Similar to the previous one, but uses a constant for the length of the array (`const len = arr.length`) to avoid repeated lookups.
5. `reversed pop`: Reverses the array and then removes an element from the end.

**Pros and Cons**

Here's a brief analysis of each approach:

* **`pop`**: Simple and straightforward, but may incur overhead due to pushing elements onto the stack during iteration.
	+ Pros: Easy to implement, minimal code changes needed.
	+ Cons: Potential performance impact due to stack usage.
* **`shift`**: Similar to `pop`, but with a slightly different implementation detail (pushing onto the stack).
	+ Pros: Similar pros and cons as `pop`.
	+ Cons: Same potential performance impact due to stack usage.
* **`i`**: Traditional `while` loop with indexing, which can be more efficient than array methods like `map()` or `forEach()`.
	+ Pros: Potential for better performance due to reduced overhead from array methods.
	+ Cons: Requires manual indexing and management of the loop counter.
* **`cached i`**: Uses a constant for the length of the array to avoid repeated lookups, which can improve performance.
	+ Pros: Reduced overhead due to caching the length value.
	+ Cons: May require additional code changes for readability.
* **`reversed pop`**: Reverses the array first and then performs the `pop` operation, which may have different performance characteristics compared to a direct `pop`.
	+ Pros: Might be faster due to reduced overhead from reversing the array initially.
	+ Cons: Additional complexity introduced by reversing the array.

**Library Usage**

The benchmark uses the `Array.prototype.pop()` and `Array.prototype.shift()` methods, which are part of the JavaScript Standard Library. These methods are implemented in V8 (the JavaScript engine used by Google Chrome) and provide a consistent interface for accessing elements at the end or beginning of an array.

**Special JS Features/Syntax**

There is no specific mention of any special JavaScript features or syntax beyond what's standard in modern JavaScript implementations.

**Alternatives**

Other alternatives to test similar benchmarking scenarios might include:

* Using other languages, such as C++ or Java, for direct array access.
* Implementing custom array manipulation functions using a language like Rust or Swift.
* Utilizing alternative data structures, like linked lists or queues, for array-like operations.

The provided benchmark on MeasureThat.net is specifically designed to test JavaScript microbenchmarks and provides valuable insights into the performance characteristics of various array access operations.

Related benchmarks:

Array sequential access (version: 0)

Comparing performance of: pop vs shift vs i vs reversed pop vs cached i

Created: one year ago by: Guest

Jump to the latest result

pop

shift

i

reversed pop

cached i

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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