Benchmark: subclass vs overwrite array original method

Script Preparation code:

class Extended extends Array {
  static fromArray(x) { return new Extended(...x) }
  push(x) { this[0]++; return super.push(x) }
}
extended = Extended.fromArray([1,1,1])

function Added(x) {
  Object.defineProperty(x, 'push', {
    configurable: false,
    enumerable: false,
    value: (v) => { x[0]++; return Array.prototype.push.call(x, v)},
  });
  return x;
}
added = new Added([1,1,1])

Tests:

Extended
extended.push(5)
Added
added.push(5)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Extended
Added

Fastest: N/A

Slowest: N/A

Latest run results:

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

LLMs can make mistakes. Check important info.

I'd be happy to help explain the provided benchmark.

**Benchmark Definition**

The benchmark is defined in JSON format, which describes two test cases: `Extended` and `Added`. The purpose of this benchmark is to compare the performance of subclassing an array (`Extended`) versus overwriting the original array method (`Added`). The script preparation code defines two classes: `Extended` and `Added`. The `Extended` class inherits from the built-in `Array` class and overrides its `push` method. The `Added` class uses a more complex approach to define its own `push` method.

**Options Compared**

There are two approaches being compared:

1. **Subclassing**: In this approach, the `Extended` class is created by subclassing the built-in `Array` class. This means that the `push` method is overridden with a custom implementation.
2. **Overwriting array method**: In this approach, the original `push` method of the array is overwritten using the `Object.defineProperty` function.

**Pros and Cons**

**Subclassing:**

Pros:

* More efficient, as it avoids the overhead of `Object.defineProperty`
* Can be more flexible, as it allows for easier modification of the subclass

Cons:

* Can lead to a larger memory footprint, due to the creation of a new class
* May have performance implications when subclassing large arrays

**Overwriting array method:**

Pros:

* More lightweight, as it doesn't create a new class
* Can be more convenient, as it avoids the need for explicit subclassing

Cons:

* Can lead to slower performance, due to the overhead of `Object.defineProperty`
* May have limitations, as it requires defining a custom `push` method with exact semantics.

**Other Considerations**

The benchmark assumes that both approaches have similar performance characteristics when dealing with small arrays. However, for larger arrays or more complex operations, the performance differences may become more pronounced.

**Library Usage**

Neither of the test cases uses any external libraries.

**Special JS Features/Syntax**

No special JavaScript features or syntax are used in this benchmark.

**Other Alternatives**

If you're interested in exploring alternative approaches, here are a few options:

1. **Prototype-based inheritance**: Instead of subclassing, you could use prototype-based inheritance to create the `Extended` class.
2. **Array.prototype.push.apply()**: You could also compare the performance of using `Array.prototype.push.apply()` instead of overwriting the original `push` method.
3. **Native array methods**: You could explore the performance of native array methods, such as `fill()` or `forEach()`, instead of custom implementations.

Keep in mind that these alternatives may have different trade-offs and requirements, so be sure to test them thoroughly to determine their suitability for your specific use case.

Related benchmarks:

subclass vs overwrite array original method (version: 0)

Comparing performance of: Extended vs Added

Created: 7 years ago by: Guest

Jump to the latest result

Extended

Added

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

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