How to Avoid Duplicate Code in a TypeScript Query Builder Using TypeORM

Learn effective techniques to eliminate duplicate code in TypeScript query builders with TypeORM, making your code more efficient and maintainable.
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How to Avoid Duplicate Code in a TypeScript Query Builder Using TypeORM

In software development, particularly when dealing with databases, avoiding duplicate code is crucial for maintaining clean and efficient code. A common situation arises when you have multiple methods handling similar query logic, as is the case in query builders using TypeORM in TypeScript. If you've found yourself duplicating code across methods like find() and findByKey(), you're not alone.

In this guide, we’ll explore how you can streamline your query builder and reduce redundancy, making your service easier to maintain.

Understanding the Problem

You may have methods in your order service that look similar and repeat the same code to build your queries. For instance:

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And another similar method:

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The challenge here is to avoid such duplication without compromising the functionalities of your methods.

Solution: Refactoring with a Common Function

Simplifying the Query Creation

To eliminate the duplicate code, you can create a helper function that handles the common query logic. Here’s how you can do it:

Create a Reusable Function: Define a function that returns the base query for your orders, including all necessary joins.

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Update Your Methods: Refactor your find() and findByKey() methods to utilize the new function, preventing redundancy in your code.

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Benefits of This Approach

Reduced Duplication: Rather than maintaining similar query logic in multiple methods, you now have a single source for the core query structure.

Improved Maintainability: Any changes to the join logic need only be made in one place, reducing risk of bugs and inconsistencies.

Increased Readability: Your methods are now cleaner and easier to understand, allowing developers to grasp the purpose of the methods at a glance.

Conclusion

Refactoring your query builder to avoid duplicate code not only enhances the maintainability of your application but also boosts your development efficiency. By consolidating shared logic into reusable functions, you ensure your code remains DRY (Don't Repeat Yourself).

By applying these techniques, you'll find yourself writing cleaner, more efficient code in TypeScript when using TypeORM. Embrace the practice of refactoring and watch your query builders transform into powerful, maintainable components.

Remember, the key to better coding practices lies in continuously seeking ways to improve and simplify your codebase.