typescript-config-surgeon

Create an eslint.config.ts using typescript-eslint's config helper, combining eslint recommended, strictTypeChecked, and stylisticTypeChecked rule sets. Place eslint-config-prettier last in the array so it disables all ESLint rules that conflict with Prettier formatting.

Path aliases defined in tsconfig paths do not resolve at runtime in Node.js by default. Install tsconfig-paths and run with node -r tsconfig-paths/register, or use ts-node with the same register flag during development.

Use bundler for Next.js and Vite projects where a bundler handles resolution. Use NodeNext for pure Node.js projects, which requires explicit .js extensions in relative imports that the compiler maps back to .ts files.

Type-aware rules using parserOptions.project run the TypeScript compiler on every linted file, which is expensive. Scope type-aware rules to only **/*.{ts,tsx} files in the flat config and enable skipLibCheck plus incremental in tsconfig to speed up checking.

With exactOptionalPropertyTypes, assigning undefined to an optional property is an error because optional means absent, not undefined. Either omit the property entirely or declare the type as boolean | undefined when undefined assignment is intentional.

The generated configuration targets ESLint 9 flat config (eslint.config.ts) and requires eslint.useFlatConfig in VS Code settings. Projects on ESLint 8 with .eslintrc.json should migrate, as the flat config format differs structurally from the legacy format.