Benchmark: "this" property vs. closure upvalue

Script Preparation code:

const O1 = class {
  a = 1;
  get() {
    return this.a;
  }
}
var o1 = new O1();

const O2 = function() {
  return {
    a: 1,
    get: function() {
      return this.a;
    }
  }
}
var o2 = new O2();


const O3 = function() {
  let a = 1;
  return {
    get: function() {
      return a;
    }
  }
}
var o3 = new O3();

Tests:

Return property class instance
o1.get()
Return property of explicitly created object
o2.get()
Return closure upvalue
o3.get()

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Return property class instance
Return property of explicitly created object
Return closure upvalue

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36

Browser/OS: Chrome 124 on Linux

View result in a separate tab

Test name	Executions per second
Return property class instance	10780022.0 Ops/sec
Return property of explicitly created object	10652499.0 Ops/sec
Return closure upvalue	10628931.0 Ops/sec

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

LLMs can make mistakes. Check important info.

**Benchmark Overview**

The provided JSON represents a JavaScript microbenchmark test case on the MeasureThat.net website. The benchmark compares the efficiency of accessing object properties versus upvalues in three different scenarios: accessing a property through an instance, explicitly creating an object, and accessing a closure upvalue.

**Options Compared**

There are three options compared:

1. **Accessing property through class instance**: `o1.get()`
2. **Accessing property of explicitly created object**: `o2.get()`
3. **Accessing closure upvalue**: `o3.get()`

**Pros and Cons of Each Approach**

### 1. Accessing Property through Class Instance (`o1.get()`)

* Pros:
	+ This approach creates a class instance with an `a` property, which is accessed through the `get()` method.
	+ The class instance has its own scope, which might lead to more predictable behavior.
* Cons:
	+ Creating a class instance and accessing its properties can be slower than directly accessing the property.

### 2. Accessing Property of Explicitly Created Object (`o2.get()`)

* Pros:
	+ This approach creates an object with an `a` property and a `get()` method, which is accessed through the property.
	+ Direct access to the property can be faster than creating a class instance.
* Cons:
	+ The object's scope might not be as predictable as the class instance's scope.

### 3. Accessing Closure Upvalue (`o3.get()`)

* Pros:
	+ This approach creates an anonymous function with a closure upvalue, which is accessed through the `get()` method.
	+ The closure upvalue can lead to more efficient access to the value.
* Cons:
	+ The scope of the closure upvalue might be less predictable than other approaches.

**Library and Purpose**

The `Object.prototype.get()` property is not explicitly used in this benchmark, but it's a potential optimization in JavaScript. In some older browsers or environments, `Object.prototype.get()` can be faster than accessing properties directly through an object.

However, modern JavaScript engines like V8 (used by Chrome) have optimized the way objects are accessed, making `Object.prototype.get()` less relevant.

**Special JS Features and Syntax**

* **Closures**: The benchmark uses closures to create anonymous functions with access to their own scope. Closures can be useful for encapsulating variables and creating private scopes.
* **Class Instances**: The benchmark creates class instances using the `class` keyword, which is a relatively new feature in JavaScript (introduced in ECMAScript 2015).
* **Arrow Functions**: The benchmark doesn't explicitly use arrow functions, but they're often used with closures to create concise and expressive code.

**Other Alternatives**

If you want to measure the efficiency of accessing object properties versus upvalues in a different context, consider using a similar setup on MeasureThat.net or creating your own benchmarking framework. You can also experiment with other JavaScript features, such as:

* **Prototypal inheritance**: Creating objects that inherit from prototypes and accessing their properties.
* **Object methods**: Accessing object methods instead of property access.
* **Function expressions**: Using function expressions instead of closures to create anonymous functions.

Keep in mind that benchmarking JavaScript code can be complex and depends on various factors, such as the specific engine, browser, or environment being used.

Related benchmarks:

"this" property vs. closure upvalue (version: 0)

Is it more efficient to access upvalues or object properties?

Comparing performance of: Return property class instance vs Return property of explicitly created object vs Return closure upvalue

Created: one year ago by: Guest

Jump to the latest result

Return property class instance

Return property of explicitly created object

Return closure upvalue

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

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