5 Code Refactoring Techniques to Improve Your Code

Introduction

Writing clean and maintainable code is essential for software development projects. It not only enhances readability but also improves collaboration among team members. One effective approach to achieve clean code is through code refactoring. Code refactoring involves making changes to the existing codebase without altering its external behavior. In this article, we will explore five code refactoring techniques that can significantly enhance the quality of your code.

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Technique 1: Extract Method

The Extract Method technique involves breaking down a long, complex function into smaller, more manageable pieces. By extracting a set of related statements into a separate method, you improve code readability and maintainability. The extracted method can be given a meaningful name that describes its purpose, making the code more self-explanatory. For example:

pythonCopy codedef calculate_total_price(items):
    # Code to calculate item prices and apply discounts
    # ...
    # ...

def print_receipt(items):
    print("Items:")
    for item in items:
        print(item)
    calculate_total_price(items)
    # ...
    # ...

In the above example, we can extract the code responsible for calculating the total price into a separate method called calculate_total_price(). This simplifies the print_receipt() function and improves its readability.

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Technique 2: Rename Variables and Functions

Meaningful names for variables and functions are crucial for code comprehension. When reviewing code, developers should be able to understand the purpose and behavior of a variable or function simply by looking at its name. If a name is unclear or misleading, it can lead to confusion and introduce bugs. By taking the time to rename variables and functions appropriately, you can significantly improve code clarity. Consider the following example:

let s = getTimestamp();
let p = calculateDistance(s);

In the above code snippet, the variables s and p have vague names that provide little context. By renaming them to timestamp and distance, respectively, the code becomes more expressive

let timestamp = getTimestamp();
let distance = calculateDistance(timestamp);

The revised code makes it clear that timestamp represents a timestamp value and distance represents the calculated distance.

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Technique 3: Remove Code Duplication

Code duplication occurs when the same or similar code appears in multiple places within a codebase. This redundancy can lead to maintenance issues, as any changes or bug fixes need to be applied to each duplicated instance. Removing code duplication improves code maintainability and reduces the chances of introducing inconsistencies. To identify duplicated code, developers can perform a code review or use automated tools. Once identified, the duplicated code can be replaced with reusable functions or extracted into shared utility methods.

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Technique 4: Simplify Conditional Expressions

Complex conditional expressions can make code difficult to read and understand. Simplifying these expressions improves code readability and reduces the potential for logical errors. One approach is to break down complex conditionals into smaller, more manageable parts. This not only makes the code easier to follow but also allows for easier testing and debugging. Additionally, you can utilize boolean variables or functions to simplify complex conditions and make them more self-explanatory.

Consider the following example:

if (isUserLoggedIn() && (isAdmin() || hasPermission())) {
    // Access granted
    // ...
}

In the above code snippet, the conditional expression is quite convoluted. By simplifying it and introducing boolean variables or functions, we can enhance code readability:

const userLoggedIn = isUserLoggedIn();
const isAdminOrHasPermission = isAdmin() || hasPermission();

if (userLoggedIn && isAdminOrHasPermission) {
    // Access granted
    // ...
}

The revised code clearly defines the conditions, making it easier to understand the access control logic.

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Technique 5: Break Large Functions into Smaller Ones

Large, monolithic functions can be challenging to comprehend and maintain. Breaking them down into smaller, focused functions improves code modularity and reusability. Each smaller function should have a well-defined responsibility, making the code easier to understand and test. By decomposing large functions, you promote code organization and allow for more flexible code modifications in the future.

public void processOrder(Order order) {
    // Code to validate order
    // ...
    // ...

    // Code to calculate shipping cost
    // ...
    // ...

    // Code to update inventory
    // ...
    // ...
}

In the above example, the processOrder() function performs multiple tasks. By breaking it down into smaller functions like validateOrder(), calculateShippingCost(), and updateInventory(), the code becomes more modular and maintainable.

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Conclusion

Code refactoring plays a vital role in improving code quality. By employing techniques like extracting methods, renaming variables and functions, removing code duplication, simplifying conditional expressions, and breaking large functions into smaller ones, you can create code that is easier to read, understand, and maintain. Remember, clean and maintainable code is crucial for long-term project success and developer productivity.

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Comments

[Anthony Fung]

Good points.

There is one thing to be aware about with (4). && and || are short circuit operators. This means that computation exits as soon as possible. In A && B, B is not evaluated if A fails. Likewise in C || D, D is not evaluated if C is true.

By breaking up the conditionals as per the example, (isAdmin() || hasPermission()) is evaluated regardless of whether isUserLoggedIn() is true. In most cases, this is insignificant. If the operations are expensive; run millions of times in a loop; or dependent on the prior conditions being true, it may be worth nesting the logic. Taking the example logic:

const userLoggedIn = isUserLoggedIn();

if (userLoggedIn) {
  const isAdminOrHasPermission = isAdmin() || hasPermission();

  if (isAdminOrHasPermission) {
      // Access granted
      // ...
  }
}