Avoid accidental redundancy Avoid accidental redundancy TL;DR: Don’t pass attributes your object already owns TL;DR: Don’t pass attributes your object already owns Problems Addressed 😔 Redundant Parameters
Unclear responsibility
Duplicated logic
Parameter pollution
Low cohesion
Parameter redundancy
Code duplication
Incomplete extracted method object Redundant Parameters Redundant Parameters Unclear responsibility Duplicated logic Parameter pollution pollution Low cohesion Parameter redundancy Code duplication Code duplication Incomplete extracted method object extracted method object Related Code Smells 💨 https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-xxxviii https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-xxxviii https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-xxxv https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-xxxv https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-ii-o96s3wl4 https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-ii-o96s3wl4 https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-x-i7r34uj https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-x-i7r34uj https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-xxix https://hackernoon.com/how-to-find-the-stinky-parts-of-your-code-part-xxix Steps 👣 Identify methods that receive owned attributes
Remove those parameters from the method signature
Replace usage with direct access to the attribute
Rename the method if needed to match the new intention Identify methods that receive owned attributes Remove those parameters from the method signature Replace usage with direct access to the attribute Rename the method if needed to match the new intention Sample Code 💻 Before  🚨 class Auto {
  constructor(motor) {
    this.motor = motor
  }

  startEngine(motor) {
    motor.ignite()
  }
}

// Usage
const motor = new Motor()
const auto = new Auto(motor)

auto.startEngine(motor)
// Redundant and maybe inconsistent class Auto {
  constructor(motor) {
    this.motor = motor
  }

  startEngine(motor) {
    motor.ignite()
  }
}

// Usage
const motor = new Motor()
const auto = new Auto(motor)

auto.startEngine(motor)
// Redundant and maybe inconsistent After 👉 class Auto {
  constructor(motor) {
    this.motor = motor
  }
    
  // 1. Identify methods that receive owned attributes    
  startEngine() {
    // 2. Remove those parameters from the method signature  
    // 4. Rename the method if needed to match the new intention
    this.motor.ignite()
  }
}

// Adjust usage to call without passing motor
const motor = new Motor()
const auto = new Auto(motor)

// 3. Replace usage with direct access to the attribute  
auto.startEngine() // No parameter needed class Auto {
  constructor(motor) {
    this.motor = motor
  }
    
  // 1. Identify methods that receive owned attributes    
  startEngine() {
    // 2. Remove those parameters from the method signature  
    // 4. Rename the method if needed to match the new intention
    this.motor.ignite()
  }
}

// Adjust usage to call without passing motor
const motor = new Motor()
const auto = new Auto(motor)

// 3. Replace usage with direct access to the attribute  
auto.startEngine() // No parameter needed Type 📝 [x]Automatic [x]Automatic [x] Safety 🛡️ This refactoring is straightforward and safe if you have good test coverage. Why is the Code Better? ✨ You remove accidental complexity. accidental complexity You stop pretending your method needs information from the outside. You reduce the cognitive load and improve encapsulation. You clarify which attributes are essential. essential You avoid passing the same data through different paths. You reduce parameter redundancy and simplify method signatures. You eliminate the possibility of passing inconsistent values since methods now directly access the object's state. This makes the code more maintainable and reduces the cognitive load when reading method calls. The methods become more cohesive by relying on their own object's data rather than external parameters. How Does it Improve the Bijection? 🗺️ This refactoring enhances the Bijection by aligning object behavior more closely with real-world entities. Bijection You match the real-world concept: an object uses what it owns. You improve the anthropomorphism and avoid unrealistic indirection. You also reduce internal and external coupling. coupling Limitations ⚠️ This works only if the method always uses the internal attribute. If you need to inject different versions for testing or variations, consider using dependency injection or a strategy pattern. dependency injection Refactor with AI 🤖 Suggested Prompt: 1. Identify methods that receive owned attributes 2. Remove those parameters from the method signature 3. Replace usage with direct access to the attribute 4. Rename the method if needed to match the new intention Suggested Prompt: 1. Identify methods that receive owned attributes 2. Remove those parameters from the method signature 3. Replace usage with direct access to the attribute 4. Rename the method if needed to match the new intention Without Proper Instructions

With Specific Instructions



ChatGPT

ChatGPT



Claude

Claude



Perplexity

Perplexity



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Copilot



You

You



Gemini

Gemini



DeepSeek

DeepSeek



Meta AI

Meta AI



Grok

Grok



Qwen

Qwen Without Proper Instructions

With Specific Instructions



ChatGPT

ChatGPT



Claude

Claude



Perplexity

Perplexity



Copilot

Copilot



You

You



Gemini

Gemini



DeepSeek

DeepSeek



Meta AI

Meta AI



Grok

Grok



Qwen

Qwen Without Proper Instructions

With Specific Instructions Without Proper Instructions Without Proper Instructions With Specific Instructions With Specific Instructions ChatGPT

ChatGPT ChatGPT ChatGPT ChatGPT ChatGPT ChatGPT ChatGPT Claude

Claude Claude Claude Claude Claude Claude Claude Perplexity

Perplexity Perplexity Perplexity Perplexity Perplexity Perplexity Perplexity Copilot

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You You You You You You You Gemini

Gemini Gemini Gemini Gemini Gemini Gemini Gemini DeepSeek

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Qwen Qwen Qwen Qwen Qwen Qwen Qwen Tags 🏷️ Encapsulation Encapsulation Level 🔋 [x]Beginner [x]Beginner [x] Related Refactorings 🔄 https://maximilianocontieri.com/refactoring-010-extract-method-object?embedable=true https://maximilianocontieri.com/refactoring-010-extract-method-object?embedable=true https://hackernoon.com/refactoring-016-building-with-the-essence?embedable=true https://hackernoon.com/refactoring-016-building-with-the-essence?embedable=true https://maximilianocontieri.com/refactoring-020-transform-static-functions?embedable=true https://maximilianocontieri.com/refactoring-020-transform-static-functions?embedable=true https://hackernoon.com/refactoring-024-replace-global-variables-with-dependency-injection?embedable=true https://hackernoon.com/refactoring-024-replace-global-variables-with-dependency-injection?embedable=true Remove Parameter
Introduce Parameter Object Remove Parameter Introduce Parameter Object Credits 🙏 Image by F. Muhammad on Pixabay F. Muhammad Pixabay This article is part of the Refactoring Series. https://maximilianocontieri.com/how-to-improve-your-code-with-easy-refactorings?embedable=true https://maximilianocontieri.com/how-to-improve-your-code-with-easy-refactorings?embedable=true

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