Dependency Injection without Frameworks

Wiring application layers explicitly with constructor functions.

Real-World Analogy (Mental Model)

“Handing a driver the car keys rather than forcing the driver to assemble the engine block before every trip.”

Key Concepts & Rules To Remember

Constructor pattern: `NewUserService(repo UserRepository) *UserService`.
Explicit parameter passing over magical reflection containers.
Enables trivial swapping with mock test doubles.

Step-by-Step Code

1. Understanding Dependency Injection without Frameworks

Wiring application layers explicitly with constructor functions. In Go, dependency injection without frameworks is designed around clarity and high runtime efficiency.

example.goGo 1.24+

func NewService(repo Repository) *Service {
    return &Service{repo: repo}
}

Common Beginner Pitfalls & Mistakes

Mistake: Misusing dependency injection without frameworks without understanding its memory or concurrency semantics.

✅ Correct Way: Always follow standard Go idioms and verify with tests.

Self Assessment

Knowledge Check

Verify your understanding with these interactive practice questions.

Quizzes

Quick checks for understanding

Multiple-choice with inline explanations—expand to see why.

What is the primary concept behind Dependency Injection without Frameworks?

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