Benchmark: Class vs Function + Prototype

Script Preparation code:

class Iterator1 {
    array = Array.from({ length: 500_000 }, () => Math.floor(Math.random() * 500) + 1);
    
    iterate() {
        let sum = 0;
        for (let i = 0; i < this.array.length; ++i) sum += this.array[i];
    }
}

const Iterator2 = function() {};

Iterator2.prototype.array = Array.from({ length: 500_000 }, () => Math.floor(Math.random() * 500) + 1);

Iterator2.prototype.iterate = function() {
    let sum = 0;
    for (let i = 0; i < this.array.length; ++i) sum += this.array[i];
};

Tests:

Class
let iterator = new Iterator1(); for (let i = 0; i < 100; ++i) { iterator.iterate(); }
Function + Prototype
let iterator = new Iterator2(); for (let i = 0; i < 100; ++i) { iterator.iterate(); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Class
Function + Prototype

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/130.0.0.0 Safari/537.36

Browser/OS: Chrome 130 on Windows

View result in a separate tab

Test name	Executions per second
Class	17.2 Ops/sec
Function + Prototype	27.7 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):

LLMs can make mistakes. Check important info.

The benchmark defined in the provided JSON compares two different approaches to creating an iterator in JavaScript—a class-based approach versus a function constructor with prototype. Here’s a detailed breakdown of what is tested and the implications of each approach.

### Approaches Compared:

1. **Class-Based Approach (`Iterator1`)**:
    - Defined using the modern ES6 `class` syntax.
    - It has an instance variable `array` populated with random numbers and a method `iterate` which sums the numbers in that array.

2. **Function/Prototype-Based Approach (`Iterator2`)**:
    - Defined using a function constructor and the prototype pattern.
    - The `array` is defined on the `Iterator2.prototype` and also contains the `iterate` method that functions in the same way as in the class-based approach.

### Benchmark Test Cases:
- **Test Case 1**: Tests the class-based iterator by creating an instance of `Iterator1` and calling the `iterate` method 100 times.
- **Test Case 2**: Tests the prototype-based iterator by creating an instance of `Iterator2` and calling the `iterate` method 100 times.

### Benchmark Results:
- The benchmark results show that the prototype-based approach (`Function + Prototype`) executed 27.68 times per second while the class-based approach (`Class`) executed 17.21 times per second. This indicates that in this particular test, the prototype approach is significantly faster.

### Pros and Cons of Each Approach:

#### 1. Class-Based Approach:
- **Pros**:
    - **Simplicity**: The class syntax is more straightforward and easier to understand, especially for developers coming from other object-oriented programming languages.
    - **Encapsulation**: It provides better encapsulation features, like private fields and methods (with class fields).
  
- **Cons**:
    - **Performance Overhead**: In certain cases, particularly in benchmarks, it might have higher overhead compared to functions due to additional complexity that comes with class instantiation.
    - **Browser Compatibility**: While modern browsers have good support for classes now, older environments may not support them.

#### 2. Function/Prototype-Based Approach:
- **Pros**:
    - **Performance**: As indicated by the benchmark results, using function constructors and prototypes can lead to better performance, particularly in specific scenarios like this where simple object instantiation and method calls are involved.
    - **Memory Efficiency**: Only a single version of methods exists on the prototype rather than being replicated for each instance.

- **Cons**:
    - **Complex Syntax**: The syntax is less intuitive for those unfamiliar with JavaScript's prototypal inheritance—leading to a steeper learning curve.
    - **Less Structured**: It lacks some of the structure and features that classes provide, such as the ability to easily create subclasses.

### Other Considerations:
- **Use Case**: The choice between these two methods often comes down to specific use cases. For instance, if performance is critical and many instances are being created, the prototype approach might be more suitable. In contrast, if code readability and maintainability are higher priorities, the class syntax may be preferred.

- **Alternative Patterns**: 
    - **Factory Functions**: Functions that create objects and can encapsulate some similar logic to classes and prototypes without using the `new` keyword. This can provide flexibility and avoid the performance pitfalls of classes.
    - **ES6 Modules**: Leveraging modules can help to structure code and encapsulate functionality while still allowing the use of classes or prototype-based patterns.
    - **Functional Programming**: JavaScript also supports a functional programming style which can be articulate and maintainable for certain applications that may not require traditional object-oriented approaches.

### Conclusion:
While both approaches are valid, the benchmark results suggest that the function/prototype approach is performant in this specific scenario. However, software engineers should choose an approach based on the specific requirements and constraints of their projects, balancing performance, readability, and maintainability.

Related benchmarks:

Class vs Function + Prototype (version: 1)

Comparing performance of: Class vs Function + Prototype

Created: one month ago by: Guest

Jump to the latest result

Class

Function + Prototype

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated one month ago):