Software Engineering Principles
Overview
Software engineering principles are the defaults that keep code understandable, maintainable, and safe to change.
Why It Matters
Principles keep teams aligned when projects get larger than one person.
Core Concepts
- Simplicity.
- Readability.
- Separation of concerns.
- Consistency.
- Explicitness where it matters.
Mental Models
Use principles as guardrails, not as religion. A good principle explains why a design is easier to evolve.
Best Practices
- Prefer clear names over comments that explain unclear names.
- Keep data flow predictable.
- Encapsulate volatility, not everything.
Common Mistakes
- Applying patterns because they are fashionable.
- Over-decoupling tiny systems.
- Letting code drift from the mental model.
Trade-offs
Consistency improves onboarding, but rigid consistency can block practical improvements.
Decision Framework
| Principle | Use when | Watch out for |
|---|---|---|
| Simplicity | The problem is small or unclear | Under-designing critical paths |
| Abstraction | The same pattern repeats | Creating indirection too early |
Examples
const statusLabel = isLoading ? "Loading" : error ? "Error" : "Ready";Simple expressions often beat clever helper layers.
Checklists
- Is the code easy to read without a guide?
- Is the abstraction earning its keep?
- Are edge cases handled where they happen?
Senior Engineer Notes
Senior engineers use principles to reduce future decision cost. They know when to delete code as well as when to add it.