Linting

Problem

Code quality issues slip through to production: unused variables, missing error handling, accessibility violations, and subtle bugs that could be caught automatically. Developers discover these issues too late in code review or worse, in production, requiring costly fixes and rework.

Solution

Analyze code statically to catch errors, enforce style, and identify problematic patterns before running tests or deploying. This provides rapid feedback and prevents entire classes of bugs.

Example

This example shows a basic ESLint configuration that catches unused variables, warns about console statements, and enforces const over let when variables aren’t reassigned.

{
  // Use ESLint's recommended ruleset as a baseline
  "extends": ["eslint:recommended"],
  "rules": {
    // Treat unused variables as errors (prevents dead code)
    "no-unused-vars": "error",
    // Warn when console.log is used (should use proper logging)
    "no-console": "warn",
    // Require const when variables aren't reassigned
    "prefer-const": "error"
  }
}

Benefits

• Catches bugs and quality issues before code reaches production or even code review.
• Enforces consistent code style across the team automatically.
• Provides instant feedback during development with IDE integration.
• Prevents entire classes of bugs like unused variables or missing error handling.

Tradeoffs

• Requires configuration and maintenance as rules evolve with the project.
• Can be noisy with false positives that require disabling rules or adding exceptions.
• May slow down development if checks are too strict or poorly configured.
• Needs team buy-in to avoid conflicts over style preferences and rules.