Benchmark: Direct property assignment vs defineProperty

Script Preparation code:

var listOfNumbers = Array(10000).fill().reduce((acc, x, i) => (acc.push(i), acc), []);

Tests:

Direct assignment
var a = listOfNumbers.reduce((acc, x) => { acc[x] = x * 2; return acc; }, {});
defineProperty
var a = listOfNumbers.reduce((acc, x) => Object.defineProperty(acc, x, { value: x * 2 }), {});

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Direct assignment
defineProperty

Fastest: N/A

Slowest: N/A

Latest run results:

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

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Let's break down the benchmark and its test cases.

**What is being tested?**

The provided JSON represents a JavaScript microbenchmark that compares two approaches for assigning values to an object:

1. **Direct property assignment**: Using the dot notation (e.g., `obj.x = x * 2`) or bracket notation (e.g., `obj[x] = x * 2`) to assign values directly to an object's properties.
2. **DefineProperty**: Using the `Object.defineProperty()` method to define a property on an object, which allows for more fine-grained control over property creation and behavior.

**Options compared**

The benchmark compares two options:

* Direct property assignment (both dot notation and bracket notation)
* DefineProperty

**Pros and Cons of each approach:**

1. **Direct property assignment**
	* Pros:
		+ Generally faster and more efficient for simple assignments.
		+ Easier to read and understand for developers who are familiar with the syntax.
	* Cons:
		+ Can be slower or less efficient when dealing with complex objects, nested structures, or large datasets (e.g., in this benchmark).
2. **DefineProperty**
	* Pros:
		+ Allows for more fine-grained control over property creation and behavior.
		+ Can be useful when working with specific use cases, such as creating getters, setters, or descriptors.
	* Cons:
		+ Typically slower and less efficient than direct assignment due to the additional overhead of the `Object.defineProperty()` method.

**Library/Features used**

None explicitly mentioned in the provided JSON. However, it's worth noting that the benchmark uses the `Array` and `reduce()` methods, which are part of the ECMAScript standard.

**Special JS features/syntax**

There is no explicit mention of special JavaScript features or syntax being used in this benchmark. The focus seems to be on comparing the performance of two specific approaches (direct property assignment and DefineProperty) rather than testing specific features.

**Other alternatives**

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

* Using `Object.assign()` instead of direct assignment.
* Implementing your own custom property creation mechanism using a library like Lodash or a homegrown implementation.
* Testing other object-oriented programming (OOP) concepts, such as classes, prototypes, or inheritance.

Keep in mind that the benchmark's focus is on comparing two specific approaches (direct property assignment and DefineProperty), so exploring alternative methods might not be directly relevant to this particular benchmark.

Related benchmarks:

Direct property assignment vs defineProperty (version: 0)

Comparing performance of: Direct assignment vs defineProperty

Created: 5 years ago by: Registered User

Jump to the latest result

Direct assignment

defineProperty

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):