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Code Refactoring using rails
This document discusses refactoring code to improve its structure and design without changing its external behavior. Refactoring includes techniques like extracting methods, moving methods between classes, simplifying conditional logic, and improving data structures. The goal of refactoring is to make code more readable, reusable, and maintainable by removing duplication, poorly structured code, and unnecessary complexity. It discusses various code smells that indicate needs for refactoring and provides examples of specific refactoring techniques at the method and class level as well as for data structures and communication between code elements.
Code Refactoring using rails
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- 2. Refactoring Code Makingcode better, may not be faster Better structured, better built More readable, more understandable Easy to work with Easy to add new features Easy to spot and fix bugs Keeping code in control Improving existing code
- 3. Contents Introduction toRefactoring Method-Level Refactoring Class and Condition Focused Refactoring Data Focused Refactoring Communication and High Level Refactoring Conclusion
- 4. What ‘REFACTORING’ is? Techniques of improving code that already exists No rules that anyone can blindly follow to improve code Techniques of recognize issues as per consciousness Applied without thinking will be dangerous
- 5. What ‘REFACTORING’ isNOT? Not debugging Not adding feature Not changing observable behavior of code Not performance improving
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- 7. When to use? Write – Scan – Refactor at the end : INCORRECT Write – Scan – Refactor regularly : CORRECT Code reviews How to use?
- 8. Code smell Duplicatedcode Long methods Comments Doesn’t tell what to do but tells us what to notice
- 9. Method Level Refactoring Preparing to refactor Grouping refactorings together Using the Extract Method refactoring Extract Method with parameters and variables Common code smells for Extract Method Using IDEs for the Extract Method refactoring The Inline Method refactoring Refactorings that remove temps Refactorings that add temps
- 10. Preparing to refactor Requirement of automated testing vs manual testing
- 11. Grouping refactorings together Individual Method(name? parameters? Temp variables? Duplicate? Too much in method?) Context of method in class (right class? similarity with other methods class) Communication between classes(inheritance)
- 12. Extract Method refactoring Smaller and specific is better Provides reusability Ease of overriding while using inheritance
- 13. Extract Method withparameters Parameters should be related to the method Extract Method with variables Temporary variables can be extracted
- 14. Code smells forusing Extract Method Long method Comments(having comments vs need comments)
- 15. Inline Method refactoring Removing method that adds no value
- 16. Refactoring to removetemps Increase temptation to write longer methods Change temps to small methods
- 17. Refactoring to addtemps Split temporary variables Introduce explaining variables Remove assignments to parameters
- 18. Split temporary variables Don’t use same temporary variable for different purposes
- 19. Introduce explaining variables To improve readability Introduce when a small method may not be required
- 20. Remove assignments to parameters Add temporary variables that assigns value to parameters may give undesired results
- 21. Class and ConditionFocused Refactoring Move Method Extract Class and Inline Class Making conditions easier to read Replacing conditions with polymorphism Replacing type code with subclasses
- 22. Move Method Movemethod from one class to another When a method interact with multiple classes then move it to the class with which it interacts more Code smell: feature envy, inappropriate intimacy, shotgun surgery
- 23. Extract Class andInline Class Code smell: Large class
- 24. Making conditions easierto read Decompose conditionals Consolidate conditionals Consolidate duplicate conditionals
- 25. Replacing conditions with polymorphism Conditions to check custom behavior
- 26. Replacing type codewith subclasses Data can be categorized into subclasses
- 27. Data Focused Refactoring Moving and encapsulating fields Working with data clumps Simplifying method calls and parameter use Pulling and pushing methods and fields
- 28. Moving and encapsulatingfields If a field is more related and being used by the other class
- 29. Working with dataclumps Preserve whole object (instead of parameters pass object) Introduce parameter object (minimize parameters list by creating a class for set of parameters)
- 30. Simplifying method callsand parameter use Rename method Remove parameter Add parameter Parameterize method (same behavior multiple methods) De-parameterize method (same type of parameter but different behavior depending on parameter) Separate Query from Modifier (split method with individual focus on functioning)
- 31. Pulling and pushingmethods and fields Pull up method Pull up field Push down method Push down field
- 32. Communication and High-Level Refactoring Refining hierarchies Extract superclass, Extract subclass, collapse hierarchy Communication refactoring Code smell: message chain, middle man Larger scale refactoring Convert procedural to OO Code smell: large classes, god classes, dumb data
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