Technical debt: as unpleasant as overnight tea, but you have to drink it.

Author：Chuan Chen 阅读数：6159人阅读分类：前端综合

Technical Debt: As Bitter as Overnight Tea, But You Have to Drink It

Overnight tea is bitter and hard to swallow, but sometimes you have to drink it to stay awake. Technical debt is the same—you know it's harmful but have to bear it. In the world of code, technical debt is as ubiquitous as shadows, lurking in everything from quick-fix temporary solutions to unfinished optimizations, silently accumulating interest.

What Is Technical Debt?

Technical debt isn't real debt but the cost of sacrificing code quality for rapid delivery. It's like using a credit card: you enjoy convenience now but pay high interest later. For example, take this code written to meet a tight deadline:

function calculateTotal(items) {
  // Hardcoded tax rate—should be configurable
  const taxRate = 0.08;
  let total = 0;
  
  // Missing boundary check for empty items
  items.forEach(item => {
    total += item.price * item.quantity;
  });
  
  // Direct rounding, ignoring financial precision requirements
  return Math.round(total * (1 + taxRate));
}

This code carries three obvious technical debts: a hardcoded tax rate, missing boundary checks, and crude monetary calculations. It works in the short term but will incur extra costs when modifying the tax rate or handling financial requirements later.

Common Types of Technical Debt

Copy-Paste Programming

Duplicate code is the most common form of technical debt. For example, multiple pages share similar form validation logic:

// Validation for Page A
function validateFormA() {
  if (!document.getElementById('name').value) {
    alert('Please enter your name');
    return false;
  }
  // Other validations...
}

// Nearly identical validation for Page B
function validateFormB() {
  if (!document.getElementById('username').value) {
    alert('Please enter a username');
    return false;
  }
  // Other validations...
}

Temporary Solutions

Quick fixes for urgent issues:

// Temporary CORS solution
app.use((req, res, next) => {
  res.header('Access-Control-Allow-Origin', '*'); // Overly permissive security policy
  next();
});

Unfinished Optimizations

Half-implemented performance optimizations:

function processLargeData(data) {
  // Only basic processing implemented
  const result = data.map(item => ({
    id: item.id,
    name: item.name
  }));
  
  // TODO: Add caching mechanism
  // TODO: Optimize large dataset handling
  return result;
}

Why Technical Debt Accumulates

Project deadlines are the most common cause. When a product manager demands, "This feature must launch tomorrow," engineers often resort to shortcuts. For example, hastily implementing a file upload feature:

// Quick-and-dirty file upload
app.post('/upload', (req, res) => {
  const file = req.files.file;
  
  // Directly save to temp directory
  file.mv(`/tmp/${file.name}`, err => {
    if (err) return res.status(500).send(err);
    
    // No file type checks
    // No size limits
    // No virus scanning
    res.send('File uploaded successfully');
  });
});

Another reason is staff turnover. New developers inheriting a project may not understand the original design intent and hesitate to modify it:

// Mystery numbers in legacy code
function calculateBonus(years) {
  return years * 0.15; // Why 0.15? No one knows anymore
}

The Cost of Technical Debt

The interest on technical debt can be higher than imagined. A classic example is the maintenance cost of incomplete responsive design:

/* Quick-fix media query */
@media (max-width: 768px) {
  .container {
    width: 100%; /* Brute-force solution */
    padding: 0;
  }
  
  /* Didn't consider component interactions */
  .sidebar {
    display: none; /* Hid critical functionality */
  }
}

This CSS temporarily solves mobile display issues but later requires:

Reimplementing sidebar functionality for mobile
Fixing layout issues caused by container width changes
Adjusting responsive behavior of other components

Managing Technical Debt

Debt Tracking

Track technical debt like accounting records. Use special comments in code:

// TECHDEBT: Needs refactoring to strategy pattern
// Owner: @devA
// Target resolution: 2023-12-01
function processPayment(method) {
  if (method === 'credit') {
    // Credit card logic
  } else if (method === 'paypal') {
    // PayPal logic
  }
  // Other payment methods...
}

Regular Repayment

Set up technical debt repayment days, e.g., the last Friday of each month:

// Repayment example: Refactor payment processing
const paymentStrategies = {
  credit: processCreditPayment,
  paypal: processPaypalPayment
  // Other payment strategies...
};

function processPayment(method) {
  const strategy = paymentStrategies[method];
  if (!strategy) throw new Error('Unsupported payment method');
  return strategy();
}

Preventing New Debt

Add quality checkpoints in code reviews. For example, use ESLint rules to block common issues:

// .eslintrc.js
module.exports = {
  rules: {
    'no-magic-numbers': ['error', { ignore: [0, 1] }], // Ban magic numbers
    'max-params': ['error', 3], // Limit function parameters
    'complexity': ['error', 5] // Limit cyclomatic complexity
  }
};

When to Accept Technical Debt

Not all technical debt is bad. When validating product concepts, appropriate debt can speed up iteration:

// Quick prototype implementation
function getRecommendedProducts() {
  // Hardcoded recommendations
  return [
    {id: 1, name: 'Test Product A'},
    {id: 2, name: 'Test Product B'}
  ];
  
  // TODO: Integrate recommendation API
  // Unnecessary before product validation
}

The key is to take on technical debt consciously, not accumulate it unknowingly. Like choosing to drink overnight tea for its caffeine boost.

Refactoring Strategies for Technical Debt

For long-accumulated debt, adopt incremental refactoring. For example, modernizing legacy code with global variables:

// Old code
let config = {}; // Global config

function initApp() {
  config.apiUrl = 'https://api.example.com';
  // Other initialization...
}

// Step 1: Encapsulate global state
const appState = (function() {
  let config = {};
  
  return {
    getConfig: () => ({...config}),
    setConfig: newConfig => config = {...config, ...newConfig}
  };
})();

// Step 2: Gradually replace references
function initApp() {
  appState.setConfig({apiUrl: 'https://api.example.com'});
}

Technical Debt and Team Culture

Healthy technical debt management requires team consensus. Create a debt dashboard to visualize status:

| Description      | Type      | Priority | Version | Status  |
|------------------|-----------|----------|---------|---------|
| Payment coupling | Design flaw | High    | v1.2    | In progress |
| No i18n          | Missing feature | Medium | v2.0    | Pending |
| Magic numbers    | Code smell | Low     | v1.5    | Planned |

Quantifying Technical Debt

Quantifying debt impact aids decision-making. For example, estimating maintenance costs:

// Estimate maintenance cost of duplicate code
const duplicateFiles = findDuplicateCode();
const maintenanceCost = duplicateFiles.length * 0.5; // 0.5 hours per file per month

// Calculate refactoring ROI
const refactorTime = 8; // Refactoring takes 8 hours
const paybackPeriod = refactorTime / maintenanceCost; // Payback period

Tool Support for Technical Debt

Modern tools help identify and manage technical debt. For example, using SonarQube to detect code quality issues:

// Code flagged by SonarQube
function setUserStatus(userId, status) {
  // Issue: No userId validation
  db.query(`UPDATE users SET status=${status} WHERE id=${userId}`);
  // Security risk: SQL injection
}

The tool detects: