Benchmark: class method vs arrow method

HTML Preparation code:

<!--your preparation HTML code goes here-->

Script Preparation code:

class Arrow{

method = ()=>{}
}
class Binder{

  constructor(){
  this.method.bind(this)
  }
  method(){}
}

Tests:

instance arrow
new Arrow().method()
instance binder
new Binder().method()
create 100 instances arrow
for(let i=0;i<1000;i++){ new Arrow().method() }
create 100 binders
for(let i=0;i<1000;i++){ new Binder().method() }
single instance 1000 calls arrow
const arrow = new Arrow() for(let i=0;i<1000;i++){ arrow.method() }
single instance 1000 calls binder
const binder = new Binder() for(let i=0;i<1000;i++){ binder.method() }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
instance arrow
instance binder
create 100 instances arrow
create 100 binders
single instance 1000 calls arrow
single instance 1000 calls binder

Fastest: N/A

Slowest: N/A

Latest run results:

Run details: (Test run date: 5 days ago)

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 18_2_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/18.2 Mobile/15E148 Safari/604.1

Browser/OS: Mobile Safari 18 on iOS 18.2.1

View result in a separate tab

Test name	Executions per second
instance arrow	28529700.0 Ops/sec
instance binder	77327824.0 Ops/sec
create 100 instances arrow	30933.9 Ops/sec
create 100 binders	93652.4 Ops/sec
single instance 1000 calls arrow	3319009.0 Ops/sec
single instance 1000 calls binder	3535389.2 Ops/sec

Autogenerated LLM Summary (model gpt-4o-mini, generated 5 days ago):

LLMs can make mistakes. Check important info.

The benchmark in question compares two different methods of defining and using methods in JavaScript classes: the **Arrow function method** and the **standard method (Binder)**. Here's a breakdown of what each approach entails, the pros and cons, and considerations based on the provided benchmark data.

### Definitions and Libraries
1. **Arrow Function Method (Arrow Class)**:
   - In this approach, `method` is defined using the arrow syntax `method = () => {}`. Arrow functions are a concise way to write functions in JavaScript, retaining the lexical `this` from the surrounding function.
   - **Pros**: 
     - The context (`this`) is lexically bound when using arrow functions, which can simplify methods that are passed as callbacks.
     - A more succinct and clean syntax.
   - **Cons**:
     - Cannot be used as constructors.
     - `this` may lead to confusion if the function needs to access the class's properties in different contexts (though this is often an advantage).

2. **Standard Method (Binder Class)**:
   - Here, the method is defined in the traditional way `method() {}`. The constructor binds `this` to the method when called via `.bind(this)`.
   - **Pros**: 
     - More flexible as it can be used in various contexts (for example, as constructors).
     - Traditional and widely understood syntax, allowing for direct access to class properties with `this`.
   - **Cons**:
     - Need to explicitly bind `this`, which can introduce boilerplate code.
     - An additional performance cost during binding at runtime.

### Test Cases Explained
The benchmark includes several test cases for measuring execution speed across various scenarios of instancing and method calling:

1. **Single Instance Method Calls**:
   - `new Arrow().method()` vs `new Binder().method()`: Measures the performance of invoking methods directly on newly created instances.
   - The results show that the instance method of Binder is significantly faster than Arrow, suggesting that standard methods may optimize initial call performance in this context.

2. **Batch Creation and Calls**:
   - `for(let i=0;i<1000;i++) { new Arrow().method() }`: Measures overhead when creating 100 instances of the Arrow class.
   - `for(let i=0;i<1000;i++) { new Binder().method() }`: Measures similar for Binder class.
   - The results suggest a higher performance hit for Arrow when creating multiple instances, likely due to additional internal processing related to arrow function context.

3. **Single Instance Multi-Call**:
   - `const arrow = new Arrow() for(let i=0;i<1000;i++) { arrow.method() }`: This tests repeated method calls on a single instance.
   - `const binder = new Binder() for(let i=0;i<1000;i++) { binder.method() }`: Same for Binder.
   - Although performance remains lower than the standard method for Arrow, the difference in execution speed narrows with repeated calls, demonstrating that context binding overhead is amortized over multiple executions.

### Performance Results Interpretation
From the benchmark results:
- The arrow function method resulted in lower executions per second compared to the standard method across all test cases.
- The Binder class, especially in single method calls and instance creation, shows superior performance, likely due to less overhead regarding the method's context and binding.

### Alternatives
Other alternatives to these methods of defining class methods include:
- **Class Fields with Traditional Functions**: Using class field syntax but defining methods normally can provide similar flexibility as standard methods while keeping modern syntax.
- **Using Prototypal inheritance**: Instead of classes, leveraging prototypes for method definitions can sometimes yield performance benefits, especially in older JavaScript environments.
- **Higher Order Functions**: Utilizing functions that return or accept other functions can provide a more functional programming style while managing context effectively.

### Conclusion
The benchmark provides insightful data on the performance implications of using arrow functions versus standard methods in JavaScript classes. While arrow functions offer a more modern syntax and a more manageable `this` context, traditional methods retain speed and flexibility, especially in scenarios involving multiple instances and method calls. As software engineers choose between these options, understanding the context of their use case is crucial for optimizing performance and maintainability.

Related benchmarks:

class method vs arrow method (version: 1)

Comparing performance of: instance arrow vs instance binder vs create 100 instances arrow vs create 100 binders vs single instance 1000 calls arrow vs single instance 1000 calls binder

Created: 5 days ago by: Guest

Jump to the latest result

instance arrow

instance binder

create 100 instances arrow

create 100 binders

single instance 1000 calls arrow

single instance 1000 calls binder

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A

Autogenerated LLM Summary (model gpt-4o-mini, generated 5 days ago):