Extract Method | Refactoring | Vs Code Tutorial

What is Extract Method?

The Extract Method is a common refactoring technique used to improve code readability and maintainability. It involves taking a portion of code from a method and placing it in a new method. This helps to simplify complex methods, making them easier to understand and test.

When to Use Extract Method?

Consider using the Extract Method when:

A method is too long or complex.
The same code is repeated in multiple places.
You want to improve code readability by breaking down large methods into smaller, self-explanatory methods.

How to Perform Extract Method

Here are the general steps to perform the Extract Method refactoring:

Identify the code segment to extract.
Determine a meaningful name for the new method.
Replace the extracted code segment with a call to the new method.
Ensure the new method has the necessary parameters and returns appropriate values.

Example of Extract Method

Let’s consider the following example in JavaScript:

Before Extract Method:

function calculateTotal(price, tax, discount) {
    let total = price + (price * tax);
    total = total - discount;
    return total;
}

In this example, the calculation of tax could be extracted into its own method.

After Extract Method:

function calculateTax(price, tax) {
    return price * tax;
}

function calculateTotal(price, tax, discount) {
    let total = price + calculateTax(price, tax);
    total = total - discount;
    return total;
}

Now, the calculateTotal method is cleaner and easier to read.

Using VS Code for Extract Method

Visual Studio Code provides built-in support for refactoring. To perform the Extract Method in VS Code:

Select the block of code you want to extract.
Right-click and choose Refactor... from the context menu.
Select Extract Method.
Provide a name for the new method and confirm.

This will automatically refactor your code and create a new method for you.

Benefits of Extract Method

Using the Extract Method technique offers several benefits:

Improved Readability: Code becomes easier to read and understand.
Reusability: Extracted methods can be reused in different parts of your code.
Ease of Testing: Smaller methods are easier to test individually.

Conclusion

The Extract Method refactoring technique is a powerful way to enhance the quality of your code. By breaking down complex methods into simpler, more manageable pieces, you can create a codebase that is easier to read, maintain, and test. Utilizing tools like Visual Studio Code can streamline this process, making refactoring more efficient.

Extract Method Tutorial