Benchmark: Uint8Array vs Uint8ClampedArray

Script Preparation code:

var arr1 = new Uint8Array(10);
var arr2 = new Uint8ClampedArray(10);

Tests:

Uint8Array
arr1[0] = 42; arr1[1] = 200; arr1[7] = arr1[1];
Uint8ClampedArray
arr2[0] = 42; arr2[1] = 200; arr2[7] = arr2[1];

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Uint8ClampedArray

109.8M/s

Uint8Array

99.6M/s

Fastest: Uint8ClampedArray (1.1x faster)

View exact numbers

✓ Uint8ClampedArray: 109,841,544 ops/sec
• Uint8Array: 99,562,096 ops/sec

Results show median performance across all community submissions. Run this benchmark yourself to verify on your device.

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Uint8Array
Uint8ClampedArray

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_7 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.7.2 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 18 on iOS 18.7

View result in a separate tab

Uint8Array

214.6M/s

Uint8ClampedArray

205.3M/s

View exact numbers

Test name	Executions per second
✓ Uint8Array	214,611,648 Ops/sec
Uint8ClampedArray	205,275,744 Ops/sec

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

LLMs can make mistakes. Check important info.

**What is tested:**
MeasureThat.net is testing the performance of two types of arrays in JavaScript: `Uint8Array` and `Uint8ClampedArray`. Specifically, it's comparing the execution time of assigning values to specific array elements.

**Options compared:**

*   **`arr1[0] = 42;`**: assigns a value of 42 to the first element (index 0) of an empty `Uint8Array`.
*   **`arr2[0] = 42;`**: assigns a value of 42 to the first element (index 0) of an empty `Uint8ClampedArray`.

**Pros and Cons:**

*   **`Uint8Array`:**
    *   Pros:
        *   `Uint8Array` is a typed array that allows you to perform binary operations on its elements.
        *   It's more memory-efficient than other arrays, especially for large datasets with only 8-bit integers or floating-point numbers.
    *   Cons:
        *   When assigning values, the array must be initialized before use. This can lead to slower performance if not done properly.
*   **`Uint8ClampedArray`:**
    *   Pros:
        *   `Uint8ClampedArray` is a typed array that extends `Uint8Array`, providing a way to specify a range of values for its elements, allowing for more flexibility in assigning values.
        *   It also has similar memory efficiency benefits as `Uint8Array`.
    *   Cons:
        *   When using the "clamped" feature, it can lead to slower performance compared to `Uint8Array` when working with values outside of the specified range.

**Library and its purpose:**
In both test cases, no libraries are explicitly mentioned. However, note that the use of a typed array (either `Uint8Array` or `Uint8ClampedArray`) requires JavaScript's built-in support for typed arrays, which is part of the ECMAScript standard.

**Special JS feature or syntax:**
None of the provided benchmark test cases require special JavaScript features or syntax beyond what's required to work with typed arrays.

**Other alternatives:**

*   If you need more complex array operations, consider using `Float32Array`, `Float64Array` for floating-point numbers, or other types like `Int8Array`, `Uint16Array`.
*   When working with binary data in JavaScript (e.g., images, audio files), use the `Blob` API or streams to manipulate raw binary data.

**Benchmark Preparation Code Explanation:**
The provided script preparation code initializes two arrays:
- `var arr1 = new Uint8Array(10);`: Creates an empty 8-bit integer array (`Uint8Array`) with a size of 10 elements.
- `var arr2 = new Uint8ClampedArray(10);`: Creates an empty 8-bit clamped integer array (`Uint8ClampedArray`) also with a size of 10 elements.

**Test Cases:**
The test cases are designed to measure the performance difference between assigning values to specific elements in these two types of arrays. The first assignment `arr1[0] = 42;` and `arr2[0] = 42;` are executed multiple times, allowing MeasureThat.net to compare their execution times and average the results over multiple runs for a fair comparison.

**Benchmark Result Explanation:**
The latest benchmark result is provided in the format of JSON. The information includes:
- `RawUAString`, `Browser`, `DevicePlatform`, `OperatingSystem`: Information about the machine running the test.
- `ExecutionsPerSecond`: The average number of assignments executed per second during the test.

Uint8Array vs Uint8ClampedArray (version: 0) Benchmark.js

Comparing performance of: `Uint8Array vs Uint8ClampedArray`

Created: 3 years ago by: Guest

Go to the latest result

Uint8Array

Uint8ClampedArray

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

Uint8Array vs Uint8ClampedArray (version: 0) Benchmark.js

Comparing performance of: Uint8Array vs Uint8ClampedArray

Created: 3 years ago by: Guest

Go to the latest result

Uint8Array

Uint8ClampedArray

Historical Performance Data aggregated from 5 community runs

Desktop Results:

Chrome 5 runs

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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

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Comparing performance of: `Uint8Array vs Uint8ClampedArray`