Refactoring 002 - Extract Method

Find some code snippets that can be grouped and called atomically.

TL;DR: Group your cohesive sentences together

Problems Addressed

• Readability

• Complexity

• Code Reuse

Related Code Smells

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Steps

1. Move the code fragment to a separate new method

2. Replace the old code with a call to the recently created method.

Sample Code

Before

object Ingenuity {
    fun moveFollowingPerseverance() {
        //take Off
        raiseTo(10 feet)

        //move forward to perseverance
        while (distanceToPerseverance() < 5 feet){
             moveForward()             
         }

        //land
        raiseTo(0 feet)
    }

After

object Ingenuity {   
    //1. Move the code fragment to a separate new method 
    private fun takeOff() {
        raiseTo(10 feet)
    }

    //1. Move the code fragment to a separate new method 
    private fun moveForwardToPerseverance() {
       while (distanceToPerseverance() < 5 feet){
             moveForward()             
         }
    }

    //1. Move the code fragment to a separate new method 
    private fun land() {
        raiseTo(0 feet)
    }

    fun moveFollowingPerseverance() {
        takeOff()
        //2. Replace the old code with a call to the recently created method.
        moveForwardToPerseverance()
        //2. Replace the old code with a call to the recently created method.
        land()
        //2. Replace the old code with a call to the recently created method.
    }
}

Type

[X] Automatic

Many IDEs support this safe refactoring

Limitations

Does not work well if you use meta-programming anti-pattern.

Tags

• Complexity

• Readability

Related Refactorings

• Move method to a new class

Credits

Image by Hreisho from Pixabay

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This article is part of the Refactoring Series.