linting

name	linting
description	ESLint and Prettier configuration, rule selection rationale, and auto-fix conventions.

Linting

Use this skill when configuring lint rules, fixing lint issues, or reviewing lint configuration changes.

Tools

• ESLint: code quality and correctness rules.
• Prettier: formatting (indentation, quotes, semicolons, line width).
• typescript-eslint: TypeScript-specific rules.

Configuration Principles

• Prettier handles all formatting. ESLint handles logic and correctness.
• No overlap: use eslint-config-prettier to disable ESLint rules that conflict with Prettier.
• Prefer rules that are auto-fixable.
• Every enabled rule must have a reason. No "enable everything" configs.

Key Rules

• no-console: warn (allow in development, catch in review).
• no-unused-vars: error (with _ prefix exemption for intentionally unused).
• @typescript-eslint/no-explicit-any: error.
• @typescript-eslint/strict-boolean-expressions: warn.
• import/order: auto-fix to enforce import grouping.
• no-restricted-imports: prevent circular dependency patterns.

Fixing

• npm run lint -- --fix for auto-fixable issues.
• Manual fixes must not change behavior — style only.
• If a rule produces false positives on valid code, disable per-line with a comment:

  // eslint-disable-next-line @typescript-eslint/no-non-null-assertion -- validated above
  const value = map.get(key)!;
  

CI Integration

• Lint runs first in CI pipeline (fast fail on style issues).
• Lint failures block merge.
• Pre-commit hook runs lint on staged files.

Adding Rules

• Propose new rules with rationale and example of what they catch.
• Test the rule against the existing codebase for false positives before enabling.
• Start as warn for new rules; escalate to error after the codebase is clean.