Benchmark: copyWithin: is it fast in Uint32Array

Script Preparation code:

var buffer = new Uint32Array(1024*1024);
for(var i=0; i< buffer.length; i++) {
    buffer[i] = Math.round(Math.random() * 256);                          
}

Tests:

UInt32Array Iteration copy
var start = 100; var length = 200; var copyToPos = 1000; for(var i=0; i< length; i++) { buffer[copyToPos++] = buffer[start + i] }
UInt32Array copyWithin
var start = 100; var length = 200; var copyToPos = 1000; buffer.copyWithin(copyToPos, start, start + length);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
UInt32Array Iteration copy
UInt32Array copyWithin

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript benchmark test case on MeasureThat.net, specifically comparing the performance of two approaches for copying data within a Uint32Array: iteration and `copyWithin` methods.

**What is being tested?**

In the first part of the JSON, a script preparation code generates a large Uint32Array buffer containing random values. This buffer serves as the source array for the benchmark.

The second part of the JSON defines two individual test cases:

1. **UInt32Array Iteration copy**: This test case uses a traditional loop to iterate through the source array and copy each element to a new position in the destination array.
2. **UInt32Array copyWithin**: This test case uses the `copyWithin` method, which is part of the Uint32Array prototype, to perform the same copying operation.

**Options being compared**

The two approaches are compared on their performance:

* **Iteration**: A traditional loop-based approach that iterates through the source array and manually updates the destination array.
* **copyWithin**: The built-in `copyWithin` method provided by the Uint32Array prototype, which is optimized for performance and efficiency.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

### Iteration

Pros:

* Easy to understand and implement
* No dependencies on external libraries or methods
* Can be used in a variety of contexts where `copyWithin` might not be supported

Cons:

* May be slower than `copyWithin` due to the overhead of manual loop iteration and array updates.
* More prone to errors, as the programmer must ensure that the loops are properly synchronized.

### copyWithin

Pros:

* Optimized for performance and efficiency by the browser's JavaScript engine
* Reduces the risk of errors, as the method is implemented in the browser's native code and is less prone to human error.
* Can be used on a wide range of browsers and devices that support Uint32Array.

Cons:

* May not be supported by older browsers or devices that don't have native support for `copyWithin`.
* Requires knowledge of the Uint32Array prototype and its methods.

**Library and purpose**

In this benchmark, no external libraries are used. The `copyWithin` method is part of the Uint32Array prototype, which is a built-in JavaScript object that provides an efficient way to manipulate arrays in memory.

**Special JS features or syntax**

There are no special JS features or syntax mentioned in this benchmark. The focus is on comparing two existing methods for copying data within a Uint32Array.

**Other alternatives**

If `copyWithin` is not supported by the browser, other approaches can be used:

1. **Manual loop iteration**: As described above.
2. **Using other array methods**, such as `splice()` or `slice()`, to achieve the desired copy operation.
3. **Using a third-party library** that provides optimized and consistent copying functionality across different browsers and devices.

In summary, this benchmark compares the performance of two approaches for copying data within a Uint32Array: iteration and `copyWithin`. The choice between these approaches depends on the specific requirements of the use case, such as performance, compatibility, and maintainability.

Latest run results:

Run details: (Test run date: 3 months ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/17.4 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
UInt32Array Iteration copy	37549.5 Ops/sec
UInt32Array copyWithin	9300636.0 Ops/sec

Related benchmarks:

copyWithin: is it fast in Uint32Array (version: 0)

Comparing the performance between iteration and copyWithin in Uint32Array

Comparing performance of: UInt32Array Iteration copy vs UInt32Array copyWithin

Created: 3 years ago by: Guest

Jump to the latest result

UInt32Array Iteration copy

UInt32Array copyWithin

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):