ESLint & Prettier

Quick Guide: ESLint 9+ flat config with defineConfig() and globalIgnores(). typescript-eslint v8+ with projectService: true. Prettier shared config with consistent formatting. eslint-config-prettier to disable conflicting rules. eslint-plugin-only-warn for better DX.

WARNING: ESLint 10 was released February 2026 and completely removes .eslintrc support. Migrate to flat config now.

<critical_requirements>

CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST use ESLint 9+ flat config with defineConfig() from eslint/config - NOT legacy .eslintrc)

(You MUST use globalIgnores() for explicit global ignore patterns - NOT bare ignores property)

(You MUST use typescript-eslint v8+ with projectService: true for typed linting)