Benchmark: Array initialization: preallocate a typed array vs vanilla preallocation

Tests:

Preallocate typed
var N = 10000; var result = new Uint8Array(N); for (var i = 0; i < N; i++) { result[i] = i; }
Preallocate vanilla
var N = 10000; var result = new Array(N); for (var i = 0; i < N; i++) { result[i] = i; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Preallocate typed
Preallocate vanilla

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 22 days ago)

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 131 on Android

View result in a separate tab

Test name	Executions per second
Preallocate typed	69382.9 Ops/sec
Preallocate vanilla	76164.0 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 26 days ago):

LLMs can make mistakes. Check important info.

This benchmark tests the performance of two different approaches to preallocating and populating arrays in JavaScript: using a **typed array** (specifically `Uint8Array`) versus using a **vanilla JavaScript array** (the standard `Array` object). Both methods are designed to perform the same task—initializing an array with a sequence of numbers from `0` to `N-1`, where `N` is set to `10,000`.

### Test Cases Breakdown

1. **Preallocate typed (Test Name: "Preallocate typed")**:
    - **Benchmark Definition**:
      ```javascript
      var N = 10000;
      var result = new Uint8Array(N);
      for (var i = 0; i < N; i++) {
          result[i] = i;
      }
      ```
    - **Description**: 
      This test creates a `Uint8Array`, which is a type of typed array that represents an array of 8-bit unsigned integers. Typed arrays provide a way to work with binary data in JavaScript, and they have a fixed length once created. The array is initialized with the indices from `0` to `N-1`.

2. **Preallocate vanilla (Test Name: "Preallocate vanilla")**:
    - **Benchmark Definition**:
      ```javascript
      var N = 10000;
      var result = new Array(N);
      for (var i = 0; i < N; i++) {
          result[i] = i;
      }
      ```
    - **Description**: 
      This test creates a standard JavaScript `Array`, initialized with `N` elements. By default, the elements are set to `undefined` until explicitly assigned a value. The loop fills the array with numbers from `0` to `N-1`.

### Performance Results
The benchmark results indicate that the typed array approach (`Preallocate typed`) outperforms the vanilla array approach (`Preallocate vanilla`) significantly:
- **Preallocate typed**: 177,150.83 Executions Per Second
- **Preallocate vanilla**: 87,661.59 Executions Per Second

### Pros and Cons of Each Approach

1. **Typed Arrays (Pros)**:
   - **Performance**: Typically faster due to optimized memory usage and access patterns. Browsers are specifically optimized for typed arrays, allowing for better performance in operations that require fixed-size buffers.
   - **Memory Efficiency**: Typed arrays require less overhead, as they store data in a more compact format directly matching the underlying binary representation.

**Cons**:
   - **Limited Flexibility**: Typed arrays have a fixed size and require more explicit management of types (e.g., `Uint8Array` can only hold values between `0` and `255`).
   - **Type Restriction**: Only certain numerical types can be used.

2. **Vanilla Arrays (Pros)**:
   - **Flexibility**: Standard arrays can grow and shrink dynamically, can hold elements of varying types (including objects, strings, and numbers), and can be easily manipulated with array methods (like `push`, `pop`, etc.).
   - **Ease of Use**: Simpler and more intuitive for quick and generic use cases.

**Cons**:
   - **Performance**: Due to overhead and less predictable memory usage, vanilla arrays may exhibit slower performance, particularly when handling large datasets or large arrays.

### Other Considerations
When deciding between typed arrays and vanilla arrays, it ultimately depends on the application's performance requirements and data management needs. For high-performance applications that deal with binary data or require memory efficiency (like games or multimedia applications), typed arrays are preferable. On the other hand, for general-purpose programming where flexibility and ease of use are more important than raw performance, vanilla arrays are sufficient.

### Alternatives
Alternatives to using these approaches may include:
- **Using Array Buffers**: If more control over byte-level operations is needed, `ArrayBuffer` can be employed in conjunction with typed arrays.
- **Higher-level Libraries**: Libraries such as **Lodash** or **Underscore** can enhance functionality and ease of use for standard arrays with additional utility functions.
- **Specialized Performance Libraries**: For significant performance tuning, libraries built for numerical computations (like **math.js** or **numeric.js**) might be helpful to leverage optimized algorithms and data structures.

Related benchmarks:

Array initialization: preallocate a typed array vs vanilla preallocation (version: 1)

Comparing performance of: Preallocate typed vs Preallocate vanilla

Created: 26 days ago by: Guest

Jump to the latest result

Preallocate typed

Preallocate vanilla

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 26 days ago):