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name: engineering-fundamentals description: | TRIGGERS: "review my code", "is this clean?", "code review", "refactor this", "code quality", "refactoring", "cleaning up", "organizing", "structuring code", "naming this", "splitting function", "extract method", "too long", "messy code", "better way", naming conventions, DRY, SOLID, clean code, refactoring, code organization, best practices. USE WHEN: Junior is refactoring, organizing code, or asking about code quality and naming. PROVIDES: Naming standards, function size limits, DRY enforcement, SOLID principles, organization. PROACTIVE: Triggers when junior mentions refactoring or improving code structure.

Engineering Fundamentals Review

"Code is read more than it is written. Write for the reader, not the machine."

When to Apply

Activate this skill when reviewing:

• Any code changes
• Function and variable naming
• Code organization and structure
• General refactoring decisions

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Review Checklist

Naming

• Descriptive: Can you understand the variable without context?
• No abbreviations: Are names spelled out? (user not usr)
• No generic names: No data, temp, info, stuff?
• Boolean prefix: Do booleans start with is, has, can, should?
• Function verbs: Do functions start with action verbs?

Function Design

• Single responsibility: Does each function do ONE thing?
• Size limit: Are functions under 20-30 lines?
• Parameter count: Are there fewer than 4 parameters?
• No side effects: Are pure functions actually pure?
• Early returns: Are guard clauses used instead of deep nesting?

Code Organization

• DRY: Is duplicated code extracted into functions?
• But not too DRY: Are abstractions justified (rule of three)?
• Cohesion: Are related things grouped together?
• Separation: Are unrelated things separated?

Comments & Documentation

• Why, not what: Do comments explain reasoning, not obvious code?
• No commented-out code: Is dead code deleted, not commented?
• JSDoc on public APIs: Are exported functions documented?

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Common Mistakes (Anti-Patterns)

1. Magic Numbers

Copy❌ if (status === 2) { ... }
   setTimeout(callback, 86400000);

✅ const STATUS = { ACTIVE: 2, INACTIVE: 1 };
   if (status === STATUS.ACTIVE) { ... }

   const ONE_DAY_MS = 24 * 60 * 60 * 1000;
   setTimeout(callback, ONE_DAY_MS);

2. Unclear Naming

Copy❌ const d = new Date();
   const temp = getUser();
   const flag = true;

✅ const createdAt = new Date();
   const currentUser = getUser();
   const isAuthenticated = true;

3. God Functions

Copy❌ function processOrder(order) {
     // 200 lines: validate, calculate, save, email, log...
   }

✅ function processOrder(order) {
     validateOrder(order);
     const total = calculateTotal(order);
     await saveOrder(order, total);
     await sendConfirmationEmail(order);
     logOrderProcessed(order);
   }

4. Deep Nesting

Copy❌ function check(user) {
     if (user) {
       if (user.active) {
         if (user.role === 'admin') {
           return true;
         }
       }
     }
     return false;
   }

✅ function check(user) {
     if (!user) return false;
     if (!user.active) return false;
     if (user.role !== 'admin') return false;
     return true;
   }

5. Premature Abstraction

Copy❌ // Used once, but has 10 configuration options
   createFlexibleReusableButton({ ... });

✅ // Just make the button
   <button className="primary">Submit</button>

   // Abstract when you need it 3+ times

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SOLID Principles Quick Check

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Socratic Questions

Ask the junior these questions instead of giving answers:

1. Naming: "Would a new developer understand this name without context?"
2. Function Size: "Can you describe what this function does in one sentence?"
3. Duplication: "I see this pattern in three places. What happens if it needs to change?"
4. Abstraction: "How many times is this abstraction actually used?"
5. Readability: "If you came back to this code in 6 months, would you understand it?"

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Naming Conventions

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Standards Reference

See detailed patterns in:

• /standards/global/naming-conventions.md

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Red Flags to Call Out