@davidteju/dev-config

Shared ESLint, Prettier, TypeScript, Vitest, and lint-staged configs for my projects.

Install from GitHub:

npm install --save-dev github:DavidTeju/dev-config

What's included

Export path	Description
./eslint/base	Base ESLint flat config + strict rules + file overrides
./eslint/svelte	Pre-composed ESLint config for SvelteKit
./eslint/nextjs	ESLint config pieces for Next.js (compose yourself)
./prettier/base	Base Prettier config (tabs, single quotes, no framework plugins)
./prettier/svelte	Prettier config with svelte + tailwind plugins
./prettier/nextjs	Prettier config with tailwind plugin
./tsconfig/node	TypeScript config for plain Node/backend services (NodeNext, ESM, strict)
./tsconfig/node-native	node preset for TypeScript that Node runs directly with type stripping (no build step)
./tsconfig/svelte	TypeScript config for SvelteKit
./tsconfig/nextjs	TypeScript config for Next.js
./vitest/node	Vitest config factory for plain Node/TS services (node env + optional @ alias)
./vitest/nextjs	Vitest config factory for Next.js (jsdom + React + @ alias)
./lint-staged/node	lint-staged config for Node/TS services
./lint-staged/svelte	lint-staged config for SvelteKit
./lint-staged/nextjs	lint-staged config for Next.js

Node / backend services

For plain Node + TypeScript services (no framework), compose the base pieces:

// tsconfig.json
{
  "extends": "@davidteju/dev-config/tsconfig/node",
  "compilerOptions": { "outDir": "dist", "rootDir": "." },
  "include": ["src", "bin", "test"]
}

// eslint.config.mjs — the base factory is framework-less; omit `framework`.
import { createConfig } from '@davidteju/dev-config/eslint';
export default await createConfig({ typeChecked: true });

// .prettierrc.mjs
export { default } from '@davidteju/dev-config/prettier/base';

// vitest.config.mjs
import { createVitestConfig } from '@davidteju/dev-config/vitest/node';
export default createVitestConfig({ rootDir: import.meta.dirname });

// lint-staged.config.mjs
export { default } from '@davidteju/dev-config/lint-staged/node';

The node tsconfig assumes ESM (verbatimModuleSyntax) — set "type": "module" in package.json. It intentionally omits outDir/rootDir (paths in an extended base resolve relative to the base file, not your project) so set those in your own tsconfig.

Running TypeScript directly with Node

For scripts and CLIs that Node runs as .ts with its built-in type stripping (Node 23.6+, no tsc build), extend node-native instead. It adds noEmit, allowImportingTsExtensions (so imports name the real .ts file) and erasableSyntaxOnly (rejects enums, namespaces and parameter properties, which type stripping cannot run), and turns off emit-only options. tsc becomes a type checker only.

// tsconfig.json
{
  "extends": "@davidteju/dev-config/tsconfig/node-native",
  "include": ["*.ts"]
}

Keep projects that compile with tsc and an outDir on node: allowImportingTsExtensions requires noEmit.

ESLint

All ESLint configs use the flat config format (ESLint 9+).

SvelteKit

svelteConfig() returns a complete, ready-to-use config array:

// eslint.config.js
import { svelteConfig } from '@davidteju/dev-config/eslint/svelte';
import svelteConf from './svelte.config.js';

export default svelteConfig({ svelteConfig: svelteConf });

Next.js

Next.js re-exports individual config pieces for you to compose with eslint-config-next:

// eslint.config.mjs
import { defineConfig, globalIgnores } from 'eslint/config';
import nextVitals from 'eslint-config-next/core-web-vitals';
import nextTs from 'eslint-config-next/typescript';
import {
  strictRules,
  testFileOverrides,
  vitestTestOverrides,
  scriptFileOverrides,
} from '@davidteju/dev-config/eslint/nextjs';

export default defineConfig([
  ...nextVitals,
  ...nextTs,
  strictRules,
  testFileOverrides,
  vitestTestOverrides,
  scriptFileOverrides,
  globalIgnores(['.next/**', 'out/**', 'build/**', 'next-env.d.ts']),
]);

What the ESLint configs enforce

strictRules -- applied to all source files:

• Prettier as an ESLint rule (prettier/prettier: error)
• TypeScript strictness: no any, consistent type imports, no non-null assertions
• Bans as any and as unknown as X double casts via AST selectors
• Code quality: complexity cap (15), no nested ternaries, no param reassignment
• Security: no eval / implied-eval

testFileOverrides -- relaxes strict rules for test files (**/*.{test,spec}.{ts,tsx}, **/__tests__/**, **/benchmark/**):

• Allows any, type casts, non-null assertions, console, and raw Date usage

vitestTestOverrides -- adds Vitest-specific lint rules (requires @vitest/eslint-plugin):

• vitest/no-conditional-in-test: bans if statements inside test bodies
• vitest/no-conditional-expect: bans conditional expect() calls

Gracefully degrades to a no-op {} if @vitest/eslint-plugin is not installed.

scriptFileOverrides -- relaxes rules for scripts/**/*.ts (CLI tooling, build scripts).

Prettier

// prettier.config.mjs (Next.js)
export { default } from '@davidteju/dev-config/prettier/nextjs';

// prettier.config.mjs (SvelteKit)
export { default } from '@davidteju/dev-config/prettier/svelte';

Both configs use tabs, single quotes, 100-char print width, and prettier-plugin-tailwindcss. The Svelte config additionally includes prettier-plugin-svelte and sets trailingComma: 'none'.

TypeScript

// tsconfig.json (Next.js)
{
  "extends": "@davidteju/dev-config/tsconfig/nextjs",
  "compilerOptions": {
    "paths": { "@/*": ["./src/*"] }
  },
  "include": ["next-env.d.ts", "**/*.ts", "**/*.tsx", ".next/types/**/*.ts"],
  "exclude": ["node_modules"]
}

// tsconfig.json (SvelteKit)
{
  "extends": "@davidteju/dev-config/tsconfig/svelte"
}

Note: paths must be defined in the consuming project's tsconfig, not the shared one, because TypeScript resolves paths relative to the tsconfig file location.

Vitest

// vitest.config.mts
import { defineConfig } from 'vitest/config';
import { createVitestConfig } from '@davidteju/dev-config/vitest/nextjs';

export default defineConfig(
  createVitestConfig({
    rootDir: import.meta.dirname,
    setupFiles: ['./src/test/setup.ts'],
    env: { DATABASE_URL: 'postgres://localhost/test' },
  })
);

The factory sets up jsdom, @vitejs/plugin-react, @ path alias to src/, v8 coverage, and scopes test discovery to src/**/*.{test,spec}.{ts,tsx}.

lint-staged

// lint-staged.config.mjs (Next.js)
export { default } from '@davidteju/dev-config/lint-staged/nextjs';

// lint-staged.config.mjs (SvelteKit)
export { default } from '@davidteju/dev-config/lint-staged/svelte';

Peer dependencies

Required: eslint, prettier, typescript

Optional (install only what your framework needs):

Peer	Used by
eslint-config-next	eslint/nextjs
prettier-plugin-svelte	prettier/svelte
prettier-plugin-tailwindcss	prettier/svelte, prettier/nextjs
vitest	vitest/nextjs
@vitest/eslint-plugin	vitestTestOverrides in eslint/base

License

MIT