Benchmark: Object.defineProperty vs Object.defineProperties

Script Preparation code:

function Item() { 
	this._a = 0;
  	this._b = 0;
  	this._c = 0;
  	this._d = 0;
}

function create(ctor) {
	var res;
  	for (var i = 0; i < 100; i++) {
		var item = ctor();
      	if (res === void 0 || Math.random() < 0.5) {
         	res = item; 
        } 
    }
  	return res;
}

function update(item) {
 	item.a = item.b;
  	item.c = item.d;
}

Tests:

Object.defineProperty
function ctor() { var obj = new Item(); Object.defineProperty(obj, "a", { get: function() { return this._a; }, set: function(value) { this._a += value; } }); Object.defineProperty(obj, "b", { get: function() { return this._b * 2; }, set: function(value) { this._b += value + 2; } }); Object.defineProperty(obj, "c", { get: function() { return this._c * 4; }, set: function(value) { this._c += value / 2; } }); Object.defineProperty(obj, "d", { get: function() { return this._d * 3; }, set: function(value) { this._d += value - 1; } }); return obj; } window.leak = update(create(ctor));
Object.defineProperties
function ctor() { var obj = new Item(); Object.defineProperties(obj, { a: { get: function() { return this._a; }, set: function(value) { this._a += value; } }, b: { get: function() { return this._b * 2; }, set: function(value) { this._b += value + 2; } }, c: { get: function() { return this._c * 4; }, set: function(value) { this._c += value / 2; } }, d: { get: function() { return this._d * 3; }, set: function(value) { this._d += value - 1; } } }); return obj; } window.leak = update(create(ctor));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Object.defineProperty
Object.defineProperties

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64; rv:148.0) Gecko/20100101 Firefox/148.0

Browser/OS: Firefox 148 on Linux

View result in a separate tab

Test name	Executions per second
Object.defineProperty	30566.1 Ops/sec
Object.defineProperties	11152.2 Ops/sec

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

LLMs can make mistakes. Check important info.

Let's dive into the benchmark.

**What is being tested?**

The provided JSON represents two test cases, each testing the performance of `Object.defineProperty` and `Object.defineProperties`. These are both methods used to define custom properties on an object.

**Options compared:**

The main difference between the two options is where they define the property descriptor. The first option (`Object.defineProperty`) defines a single property at a time, while the second option (`Object.defineProperties`) defines multiple properties in a single call.

**Pros and Cons of each approach:**

1. `Object.defineProperty`:
	* Pros:
		+ More fine-grained control over property definitions.
		+ Can be more efficient for simple cases with few properties.
	* Cons:
		+ Requires multiple calls to define all desired properties.
		+ May incur additional overhead due to the need for separate method calls.
2. `Object.defineProperties`:
	* Pros:
		+ More concise and readable, as all property definitions are combined in a single call.
		+ Reduces overhead compared to multiple separate method calls.
	* Cons:
		+ Less fine-grained control over property definitions.
		+ May be slower due to the need for more complex processing.

**Other considerations:**

The benchmark is likely testing the performance implications of these different approaches. In general, `Object.defineProperties` might incur a slight overhead due to its more complex processing, but it can also provide better performance in certain scenarios, such as when working with large numbers of properties or when property definitions are tightly coupled.

**Library and syntax:**

No libraries are used in this benchmark, as it only tests built-in JavaScript features. However, it's worth noting that both `Object.defineProperty` and `Object.defineProperties` use the same syntax for defining properties: `{ property-name: { get: function, set: function } }`.

No special JS features or syntax are being tested in this benchmark.

**Alternatives:**

Other alternatives to `Object.defineProperty` and `Object.defineProperties` include:

* Using the `Map` data structure to store property descriptors
* Implementing custom property descriptor objects using a different syntax (e.g., using getters, setters, and methods)
* Using library functions like Lodash's `setObjectProperty` or jQuery's `.prop()` method

However, these alternatives are not typically used in production code and may not provide the same level of control or performance as `Object.defineProperty` and `Object.defineProperties`.

Related benchmarks:

Object.defineProperty vs Object.defineProperties (version: 0)

Comparing performance of: Object.defineProperty vs Object.defineProperties

Created: 3 years ago by: Guest

Jump to the latest result

Object.defineProperty

Object.defineProperties

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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