Benchmark: JS Object Creation vs Pooling

Script Preparation code:

const n = 10000
var arr = new Array(n).fill(0);
for (let i = 0; i < n; i++) {
  arr[i] = i;
}

Tests:

Dynamic Creation
const result = []; for (let i = 0; i < arr.length; i++) { result.push({ x: arr[i], y: arr[i] + 1 }); }
Pooling
const result = []; const obj = { x: 0, y: 0 }; for (let i = 0; i < arr.length; i++) { obj.x = arr[i]; obj.y = arr[i] + 1; result.push(obj); }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Dynamic Creation
Pooling

Fastest: N/A

Slowest: N/A

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

LLMs can make mistakes. Check important info.

Let's break down the JavaScript microbenchmark you provided.

**Benchmark Definition**

The benchmark tests two approaches to create arrays of objects:

1. **Pooling**: This approach creates an initial array `arr` with 10,000 elements and fills it with zeros. Then, for each element in the array, a new object is created and added to an empty result array.
2. **Dynamic Creation**: In this approach, an empty result array is created initially. For each element in the `arr` array, a new object is created on the fly using the elements from `arr`, and then that object is pushed into the result array.

**Options Compared**

The benchmark compares two options:

* **Pooling**: Creates an initial array of objects and then creates new objects within that array.
* **Dynamic Creation**: Creates new objects directly within the result array, without creating a pre-allocated array.

**Pros and Cons**

* **Pooling**:
	+ Pros: Can be faster because it avoids the overhead of creating a large number of objects on the fly.
	+ Cons: Requires more memory upfront to create the initial array, which may not be desirable in all scenarios.
* **Dynamic Creation**:
	+ Pros: Uses less memory upfront and can be more suitable for scenarios where the number of objects is not known beforehand.
	+ Cons: Can be slower because it involves creating new objects on the fly.

**Library Usage**

There are no libraries explicitly mentioned in this benchmark, but it's worth noting that if a library were used to implement these approaches (e.g., Lodash or Array.prototype.map()), the results might differ due to the additional overhead of the library.

**Special JS Features/Syntax**

None of the provided benchmark code uses any special JavaScript features or syntax. It only uses basic JavaScript constructs like arrays, loops, and object creation.

**Alternative Approaches**

Other approaches to creating arrays of objects could include:

* **Using `Array.prototype.map()`**: Instead of using a loop to create new objects, you could use the `map()` method to create an array of transformed objects. This approach is often more concise and efficient.
* **Using a library like Lodash's `map()` function**: Similar to the previous suggestion, using a library's implementation of `map()` can provide a performance boost compared to the basic JavaScript implementation.

Keep in mind that these alternative approaches might have different performance characteristics depending on the specific use case and requirements.

Latest run results:

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

User agent: Mozilla/5.0 (Linux; Android 10; K) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Mobile Safari/537.36

Browser/OS: Chrome Mobile 118 on Android

View result in a separate tab

Test name	Executions per second
Dynamic Creation	401.0 Ops/sec
Pooling	456.6 Ops/sec

Related benchmarks:

JS Object Creation vs Pooling (version: 0)

Comparing performance of: Dynamic Creation vs Pooling

Created: one year ago by: Registered User

Jump to the latest result

Dynamic Creation

Pooling

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):