Benchmark: Object.defineProperties vs individual Object.defineProperty calls

Script Preparation code:

obj = {};
let targets = [obj];
for (let levels = 0; levels < 2; levels++) {
  for (let i = 1; i <= 10; i++)
    targets.forEach(tgt => tgt[i] = {});
  targets = targets.flatMap(tgt => Object.keys(tgt).map(key => tgt[key]));
}

Tests:

Bulk definition
function _copy(data) { const other = {}; const descs = Object.getOwnPropertyDescriptors(data); for (let prop in descs) { let desc = descs[prop]; desc.value = _copy(desc.value); } Object.defineProperties(other, descs) } _copy(obj);
Individual definition
function _copy(data) { const descs = Object.getOwnPropertyDescriptors(data); const other = {}; for (let prop in descs) { let desc = descs[prop]; desc.value = _copy(desc.value); Object.defineProperty(other, prop, desc); } } _copy(obj);
Simple assignment
function _copy(data) { const descs = Object.getOwnPropertyDescriptors(data); const other = {}; for (let prop in descs) { let desc = descs[prop]; desc.value = _copy(desc.value); other[prop] = desc.value; } } _copy(obj)

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Bulk definition
Individual definition
Simple assignment

Fastest: N/A

Slowest: N/A

Latest run results:

No previous run results

This benchmark does not have any results yet. Be the first one to run it!

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

LLMs can make mistakes. Check important info.

Let's dive into the explanation of the provided benchmark.

**Benchmark Definition**

The benchmark is comparing three approaches to define properties on an object in JavaScript:

1. **Individual Object.defineProperty calls**: This approach involves defining each property individually using `Object.defineProperty()`.
2. **Bulk definition using Object.defineProperties**: This approach involves defining all properties at once using `Object.defineProperties()`.

**Options Compared**

The benchmark is comparing the performance of these two approaches, with a third option ("Simple assignment") for reference.

**Pros and Cons**

* **Individual Object.defineProperty calls**:
	+ Pros: Easy to understand and implement, allows for more control over property definition.
	+ Cons: Can be slower due to repeated function calls.
* **Bulk definition using Object.defineProperties**: 
	+ Pros: Faster than individual calls, can reduce overhead of repeated function calls.
	+ Cons: Requires knowledge of `Object.getOwnPropertyDescriptors()` and `Object.defineProperties()`, can be more complex to understand.
* **Simple assignment**:
	+ Pros: Simple and easy to understand, allows for direct assignment of property values.
	+ Cons: May lead to slower performance due to repeated assignments.

**Library Usage**

None of the benchmark definitions use any external libraries. However, `Object.getOwnPropertyDescriptors()` is a built-in JavaScript function that returns an object containing metadata about each property in an object.

**Special JS Feature/Syntax**

The benchmark uses some specific syntax:

* `_copy` function: This is a custom function used to recursively copy property values.
* `Object.getOwnPropertyDescriptors()`: This function is used to get the metadata of properties in an object.

**Other Considerations**

The benchmark prepares the test object and sets up the necessary data before running each test case. The HTML preparation code is empty, indicating that no external dependencies or setup are required for this benchmark.

If you're interested in exploring alternative approaches, some other options might include:

* Using `Object.create()` to create a new object and define properties on it.
* Using a library like Lodash's `cloneDeep()` function to recursively copy property values.
* Using a different approach, such as using an array of property definitions and applying them individually.

Related benchmarks:

Object.defineProperties vs individual Object.defineProperty calls (version: 4)

Comparing performance of: Bulk definition vs Individual definition vs Simple assignment

Created: 4 years ago by: Registered User

Jump to the latest result

Bulk definition

Individual definition

Simple assignment

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):