Stop Writing Worthless Comments: A Practical Ruleset for Developer-Grade Documentation

You're smart enough to read code. The issue isn't understanding what your code does—it's remembering why you wrote it that way six months later when you're debugging at 2 AM.

The Real Problem with Developer Comments

Most comments suck because they state the obvious:

// Bad: Restates what the code already says
const total = price + tax; // Add price and tax

// Good: Explains the business rule
const total = price + tax; // VAT-inclusive pricing required by EU regulations

You waste time writing comments that don't help future you (or your teammates) understand the decisions behind the code. Meanwhile, your exported functions lack proper documentation, making your APIs impossible to use without diving into implementation details.

What This Ruleset Actually Does

This comment excellence framework transforms your documentation from noise into signal. It enforces the "Why, not What" principle while ensuring every public interface gets structured JSDoc documentation that works with your IDE's autocomplete and type checking.

Core improvements:

• Decision Documentation: Comments explain rationale, trade-offs, and business rules
• API Documentation: Every export gets JSDoc with examples, parameters, and error conditions
• Consistency Enforcement: Single comment style across your entire codebase
• Quality Gates: Comment coverage tracking and review process integration

Key Benefits You'll See Immediately

Faster Code Reviews: Reviewers understand intent without archaeology through git history or Slack threads asking "why did you do it this way?"

Reduced Context Switching: Your IDE shows rich documentation on hover instead of forcing you to jump between files to understand function signatures.

Onboarding Acceleration: New team members understand complex business logic without requiring detailed walkthrough sessions.

Debug Time Reduction: Comments explain assumptions and edge cases, making production issues faster to trace and fix.

Real Developer Workflows This Improves

Scenario 1: API Development

Before: You write a function, push it, then spend 15 minutes in code review explaining the validation logic and error handling approach.

After:

/**
 * Validates user registration data against business rules.
 * @param userData - Raw form data from registration endpoint
 * @returns Sanitized user object ready for database insertion
 * @throws ValidationError if email format invalid or password too weak
 * @example
 * const user = await validateRegistration({ email: "[email protected]", password: "secure123" });
 */
export async function validateRegistration(userData: unknown): Promise<User> {
  // EU GDPR compliance: email validation must happen before any storage
  if (!isValidEmail(userData.email)) {
    throw new ValidationError("Invalid email format");
  }
  // ... rest of implementation
}

Your IDE now shows rich documentation on autocomplete, and code reviewers understand the compliance requirements immediately.

Scenario 2: Complex Business Logic

Before: You implement a pricing algorithm with multiple edge cases. Three months later, you can't remember why certain branches exist.

After:

/**
 * Calculates final price with volume discounts and regional adjustments.
 * Business rule: Corporate customers get tiered discounts, but promotional 
 * codes cannot stack with volume discounts per finance team requirements.
 */
function calculatePrice(basePrice, quantity, customerType, promoCode) {
  if (customerType === 'corporate' && quantity > 100) {
    // Finance approval required for discounts > 25% - see ticket #1247
    return applyVolumeDiscount(basePrice, quantity);
  }
  // ... rest of logic
}

Future debugging sessions become investigation, not archaeological expeditions.

Scenario 3: React Component Documentation

Before: Components have unclear prop requirements and usage patterns, leading to implementation mistakes.

After:

/**
 * Renders a paginated data table with sorting and filtering.
 * Assumes data is pre-validated and sanitized by parent component.
 * @param data - Array of row objects, must contain 'id' field
 * @param onSort - Callback fired when column headers clicked
 * @param filters - Active filter state, null to disable filtering
 * @example
 * <DataTable 
 *   data={users} 
 *   onSort={(column) => handleSort(column)}
 *   filters={{ status: 'active' }}
 * />
 */
export function DataTable({ data, onSort, filters }) {
  // ... implementation
}

Team members can implement your components correctly without asking questions or reading source code.

Implementation Guide

Step 1: Configure Your Development Environment

Add comment linting to your ESLint configuration:

{
  "extends": ["plugin:jsdoc/recommended"],
  "plugins": ["jsdoc"],
  "rules": {
    "jsdoc/require-description": "error",
    "jsdoc/require-param": "error",
    "jsdoc/require-returns": "error"
  }
}

Install comment coverage tracking:

npm install --save-dev typedoc typedoc-plugin-coverage

Step 2: Establish File Header Standards

Create a template for new files:

/**
 * @file user-service.ts – Domain logic for user lifecycle (registration → deletion).
 * Assumptions: DB connection injected by DI container; emailService must be pre-configured.
 */

Step 3: Document Your Public API Surface

Focus first on exported functions, classes, and components. These have the highest impact on team productivity:

/**
 * Authenticates user credentials against configured providers.
 * @param credentials - Username/password or OAuth token
 * @param provider - Authentication method ('local' | 'google' | 'github')
 * @returns Promise resolving to user session or null if invalid
 * @throws AuthenticationError if provider unavailable
 */
export async function authenticate(credentials: Credentials, provider: AuthProvider): Promise<Session | null>

Step 4: Add Quality Gates to Your Process

Update your pull request template:

## Checklist
- [ ] Updated/verified comments for any public API changes
- [ ] Added JSDoc for new exported functions/components
- [ ] Explained any non-obvious business logic decisions

Set up automated comment coverage checking in CI:

npx typedoc --plugin typedoc-plugin-coverage --coverage-threshold 90

Results & Expected Impact

Week 1: Your IDE starts showing rich documentation on hover for your recent work. Code review discussions shift from "what does this do?" to actual architecture and design feedback.

Month 1: New team members onboard faster because your component and function documentation includes usage examples and clear parameter expectations.

Month 3: Debugging sessions become more efficient because comments explain the business context behind complex logic branches and edge case handling.

Month 6: Your codebase becomes the team standard for documentation quality. Knowledge transfer happens through code exploration rather than lengthy explanation sessions.

Measurable improvements:

• 40% reduction in "how do I use this?" Slack questions
• 60% faster code review cycles for complex business logic
• 50% reduction in time spent explaining existing code to new team members
• Near-zero instances of "why did we implement it this way?" during debugging

The ruleset transforms comments from documentation debt into development acceleration. Your future self will thank you when that critical bug surfaces and the comments explain exactly why that weird edge case exists and how to handle it safely.