Incomplete objects cause lots of issues.

Problems

• Mutability
• Incomplete objects
• Concurrency inconsistencies between creation and essence setting.
• Setters

Solutions

• Pass the object’s essence on creation

Examples

• Some persistence frameworks in static typed languages require an empty constructor.

Exceptions

• Stateless objects. Always better solution than static class methods.

Sample Code

Wrong

Right

TL;DR: A Compilation of bad smells in code.

In this series, we will see several symptoms and situations that make us doubt the quality of our developments.

We will present possible solutions.

Most of these smells are just clues of something that might be wrong. They are not rigid rules.

Code Smells

Protocol is empty (with setters/getters).

If we ask a domain expert to describe an entity he/she would hardly tell it is ‘a bunch of attributes’.

Problems

• No Encapsulation.
• No mapping to real world entities.
• Duplicate Code
• Coupling

Solutions

1) Find Responsibilities.

2) Protect your attributes.

3) Hide implementations.

4) Delegate

Examples

• DTOs

Sample Code

Wrong

Right

TL;DR: Don’t import too much.

Problems

• Coupling
• Single Responsibility Principle violation
• Low Cohesion

Solutions

1. Break the class

2. Hide intermediate accidental implementation

Sample Code

Wrong

Right

Detection

We can set a warning threshold on our linters.

Tags

• Coupling
• Ripple Effect

Conclusion

We need to think about dependencies when building our solutions to minimize Ripple Effect.

Relations

More Info

TL;DR: Create a clear contract. Expect just one protocol.

Problems

• Fail Fast principle violation
• Error prune
• Readability
• If polluting
• Nulls
• Bad Cohesion

Solutions

1. Take just one “kind” of input

2. Arguments should adhere to a single protocol.

Sample Code

Wrong

Right

Detection

We can detect this kind of methods when they do different things…

TL;DR: Don’t use abbreviations in subclasses

Problems

• Readability
• Mistakes

Solutions

1. Rename your classes to provide context
2. Use modules, namespaces or fully qualified names

Sample Code

Wrong

abstract class PerserveranceDirection { 
}class North extends PerserveranceDirection {}
class East extends PerserveranceDirection {}
class West extends PerserveranceDirection {}
class South extends PerserveranceDirection {}//Subclasses have short names…

TL;DR: Use asserts with declarative descriptions.

Problems

• Readability
• Hard debugging
• Time waste

Solutions

1. Put a nice descriptive assertion
2. Share guides for problem-solving

Sample Code

Wrong

<?public function testNoNewStarsAppeared(): void
  {
     $expectedStars = $this->historicStarsOnFrame();
     $observedStars = $this->starsFromObservation();
     //These sentences get a very large collection     $this->assertEquals($expectedStars, $observedStars)…

When creating events, we should decouple the trigger from the action.

TL;DR: Name your functions acording to what happened.

Problems

• Observer Pattern violation
• Coupling

Solutions

1. Name the events after “what happened”, not “what you should do”.

Sample Code

Wrong

const Item = ({name, handlePageChange)} =>
  <li onClick={handlePageChange}>
    {name}
  </li>//handlePageChange is coupled to what you…