Benchmark: Class method / instance method / bind this

Script Preparation code:

window.A = class {
    a() {}
}

window.B = class {
    b = () => {};
}

window.C = class {
    constructor() {
        this.c = this.c.bind(this);
    }

    c() {}
}

Tests:

Call class method
(new A()).a();
Call instance method
(new B()).b();
Call bound method
(new C()).c();

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Call class method
Call instance method
Call bound method

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 4 years ago)

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36

Browser/OS: Chrome 85 on Mac OS X 10.15.7

View result in a separate tab

Test name	Executions per second
Call class method	6294433.5 Ops/sec
Call instance method	3080786.0 Ops/sec
Call bound method	5557000.5 Ops/sec

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

LLMs can make mistakes. Check important info.

I'll explain the JavaScript microbenchmark you've provided.

**Benchmark Overview**

The benchmark measures the performance of calling class methods (instance methods bound to `this`) in different scenarios.

**Script Preparation Code**

The script preparation code defines three classes:

1. `A`: a simple class with an instance method `a()`.
2. `B`: another class with an instance method `b()`, which is a traditional arrow function.
3. `C`: a class that uses the "bind this" pattern to create a bound version of its `c()` method.

**Html Preparation Code**

The html preparation code is empty, indicating that no HTML-specific tests are performed in this benchmark.

**Test Cases**

There are three test cases:

1. **Call class method**: calls the instance method `a()` of class `A` using `(new A()).a()`.
2. **Call bound method**: calls the bound version of the instance method `c()` of class `C` using `(new C()).c()`. Note that this is done in the constructor, which means it's called before the object is fully constructed.
3. **Call instance method**: calls the traditional arrow function `b()` of class `B` using `(new B()).b()`.

**Library Used**

There are no external libraries used in this benchmark.

**Special JS Feature or Syntax**

The "bind this" pattern used in class `C` is a special syntax to create a bound version of an instance method. This allows the method to be called without explicitly passing `this` as an argument, even if the context changes. In this case, it's used to bind the method to the constructor function itself, allowing it to be called before the object is fully constructed.

**Options Compared**

The benchmark compares the performance of calling class methods in different scenarios:

1. **Direct instance call**: calls the instance method directly using `(new A()).a()`.
2. **Bound method call**: uses the "bind this" pattern to create a bound version of the instance method and then calls it using `(new C()).c()`. This allows the method to be called without explicitly passing `this` as an argument.
3. **Traditional arrow function call**: calls the traditional arrow function `b()` using `(new B()).b()`.

**Pros and Cons**

Here are some pros and cons of each approach:

1. **Direct instance call**:
	* Pros: simple, straightforward
	* Cons: may not work well if `this` is not passed explicitly or if the context changes
2. **Bound method call**:
	* Pros: allows for more flexibility in calling methods without passing `this`
	* Cons: requires explicit use of the "bind this" pattern, which can be confusing for some developers
3. **Traditional arrow function call**:
	* Pros: straightforward and easy to understand
	* Cons: may not work well with older browsers or environments that don't support arrow functions

**Other Alternatives**

Some other approaches could be used in place of the "bind this" pattern, such as:

1. Using `call()` or `apply()` to pass `this` explicitly.
2. Using a proxy object to create a bound version of the method.
3. Using a decorator function to bind methods.

However, these alternatives may have their own pros and cons, and may not offer significant performance benefits over the "bind this" pattern in most cases.

Related benchmarks:

Class method / instance method / bind this (version: 0)

Comparing performance of: Call class method vs Call instance method vs Call bound method

Created: 4 years ago by: Guest

Jump to the latest result

Call class method

Call instance method

Call bound method

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

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