Benchmark: class private prop and read prop fix test5

Script Preparation code:

class Test1 {
  constructor(name) {
    this.name = name;
  }
}

class Test2 {
  constructor(name) {
    this._name = name;
  }

  get name() {
    return this._name;
  }
}

class Test3 {

  constructor(name) {
    Object.defineProperties(this, {
      name: {
        enumerable  : true,
        configurable: false,
        get() {
          return name;
        }
      }
    });
  }
}

class Test4 {
  #name;

  constructor(name) {
    this.#name = name;
  }

  get name() {
    return this.#name;
  }
}

class Test5 extends Test4 {
}

const a20 = new Array(20).fill(undefined);

function test1() {
  const a = new Test1('test');
  return a20.map(() => a.name === 'test');
}

function test2() {
  const a = new Test2('test');
  return a20.map(() => a.name === 'test');
}

function test3() {
  const a = new Test3('test');
  return a20.map(() => a.name === 'test');
}

function test4() {
  const a = new Test4('test');
  return a20.map(() => a.name === 'test');
}

function test5() {
  const a = new Test5('test');
  return a20.map(() => a.name === 'test');
}

Tests:

test1
test1();
test2
test2();
test3
test3()
test4
test4();
test5 (by extends)
test5();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
test1
test2
test3
test4
test5 (by extends)

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/110.0.0.0 Safari/537.36

Browser/OS: Chrome 110 on Windows

View result in a separate tab

Test name	Executions per second
test1	9353361.0 Ops/sec
test2	9555166.0 Ops/sec
test3	830130.4 Ops/sec
test4	9582554.0 Ops/sec
test5 (by extends)	7384350.0 Ops/sec

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

LLMs can make mistakes. Check important info.

Measuring JavaScript performance is a complex task, and MeasureThat.net provides a great platform for testing various scenarios.

**Benchmark Definition**

The provided JSON represents a benchmark that tests the execution time of different test cases in a JavaScript class with private properties and read-only properties. The benchmark defines five test cases:

1. `test1`: Creates an instance of `Test1` and checks if the `name` property is equal to `'test'`.
2. `test2`: Creates an instance of `Test2` and checks if the `name` property is equal to `'test'`.
3. `test3`: Uses `Object.defineProperties` to define a read-only property `name` on `Test3`. Then, it creates an instance of `Test3` and checks if the `name` property is equal to `'test'`.
4. `test4`: Creates an instance of `Test4` with a private property `_name` using the `#` symbol (also known as "private fields" in JavaScript). The test case then checks if the `name` property is equal to `'test'`.
5. `test5`: Extends `Test4` and creates an instance of `Test5`. It then checks if the `name` property is equal to `'test'`.

**Options Compared**

The benchmark compares different approaches for accessing private properties:

* `Test1` uses a public `name` property.
* `Test2` uses a getter function for its `name` property, which is also public.
* `test3` uses `Object.defineProperties` to define a read-only property `name`.
* `test4` uses the `#` symbol (private fields) to create a private `_name` property.
* `test5` extends `Test4` and inherits its private properties.

**Pros and Cons**

Here's a brief summary of the pros and cons of each approach:

1. **Public `name` property**: Easy to access, but may not be intended for external use (e.g., due to security concerns). Pros: easy to implement, well-supported in most browsers.
2. **Getter function for `name` property**: Explicitly controls access to the private property. Pros: provides fine-grained control over accessibility; cons: can lead to boilerplate code.
3. **`Object.defineProperties`**: Allows for more granular control over property behavior. Pros: flexible, but requires understanding of property descriptors. Cons: may be less familiar to developers.
4. **Private fields (`#` symbol)**: Introduced in ECMAScript 2020, provides a concise way to declare private properties. Pros: concise and expressive; cons: relatively new feature, may not be supported in older browsers or environments.
5. **Inheritance with `extends`**: Allows for code reuse by inheriting private properties from a parent class. Pros: promotes modularity, efficient code reuse; cons: may require additional setup (e.g., using classes).

**Other Considerations**

When choosing an approach, consider the following:

* Security: If accessing private properties can be exploited for malicious purposes, use a more secure approach like `Object.defineProperties` or private fields.
* Code readability and maintainability: For simple cases, a public property might be sufficient. However, if you need fine-grained control over accessibility, consider using getters or the `#` symbol.
* Browser support: If targeting older browsers, you may need to use more traditional approaches like getter functions.

**Alternative Implementations**

If you want to test other aspects of JavaScript performance, MeasureThat.net offers various benchmarks for:

* Object creation and garbage collection
* Function performance (e.g., using `Function` constructors or `eval`)
* String manipulation
* Regular expressions
* JSON parsing
* Canvas rendering

These additional benchmarks can help you identify performance bottlenecks in different areas of your JavaScript codebase.

Related benchmarks:

class private prop and read prop fix test5 (version: 3)

class private prop and read prop

Comparing performance of: test1 vs test2 vs test3 vs test4 vs test5 (by extends)

Created: one year ago by: Registered User

Jump to the latest result

test1

test2

test3

test4

test5 (by extends)

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):