Beginner LevelSoftware Engineering Principles
What are DRY (Don't Repeat Yourself), KISS (Keep It Simple, Stupid), and YAGNI (You Aren't Gonna Need It)?
❓ Interview Prompt: Explain the core Software Engineering principles DRY, KISS, and YAGNI with real-world refactoring examples.
Core Software Engineering Guidelines:
1
DRY (Don't Repeat Yourself): Every piece of knowledge or business logic must have a single, unambiguous representation within a system. Avoid duplicate code blocks by refactoring into shared functions or modules.
2
KISS (Keep It Simple, Stupid): Systems work best if they are kept simple rather than made complicated. Avoid over-engineering, unnecessary abstractions, or overly clever trick code.
3
YAGNI (You Aren't Gonna Need It): Do not implement features or abstractions until they are explicitly needed. Premature abstraction increases complexity without providing current value.
Code Implementation Example
typescript
// ❌ Violating DRY & KISS: Duplicated complex tax calculation
function calculateOnlineTax(amount: number) { return amount * 0.2 + (amount > 100 ? 5 : 0); }
function calculateInStoreTax(amount: number) { return amount * 0.2 + (amount > 100 ? 5 : 0); }
// ✅ Refactored with DRY & KISS: Single clean utility function
function calculateTax(amount: number, flatFeeThreshold = 100): number {
const baseTax = amount * 0.2;
const flatFee = amount > flatFeeThreshold ? 5 : 0;
return baseTax + flatFee;
}💡Applying DRY and KISS to eliminate duplicated tax calculation logic.
🎯 Interview Key Takeaway
Adhere to DRY to eliminate code duplication, KISS for clarity, and YAGNI to prevent premature over-engineering.
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