@zerly/eslint-config

Opinionated ESLint flat config preset for NestJS + TypeScript projects.

What's included

| Plugin | Rules | |----------------------------|---------------------------------------------------------------------| | typescript-eslint | Strict type-aware rules, naming conventions, explicit return types | | eslint-plugin-sonarjs | Code smell detection, cognitive complexity | | eslint-plugin-rxjs-x | RxJS best practices (no floating observables, no nested subscribes) | | eslint-plugin-unicorn | Modern JS patterns, node: protocol enforcement | | eslint-plugin-security | Common backend vulnerability patterns | | eslint-plugin-no-secrets | Accidentally committed credentials detection | | eslint-plugin-import-x | Import ordering and deduplication | | eslint-plugin-jsdoc | JSDoc validation (validate existing, not require everywhere) | | eslint-plugin-prettier | Prettier integration | | eslint-config-prettier | Disables formatting rules that conflict with Prettier |

Installation

npm install -D @zerly/eslint-config

All plugins are bundled as direct dependencies — no extra installs needed.

Usage

// eslint.config.mjs
import { defineNestjsConfig } from '@zerly/eslint-config';

export default [
  ...defineNestjsConfig({ tsconfigRootDir: import.meta.dirname }),
];

With Nx

Nx-specific rules (enforce-module-boundaries, dependency-checks) stay in your own config:

// eslint.config.mjs
import nx from '@nx/eslint-plugin';
import jsoncParser from 'jsonc-eslint-parser';
import { defineNestjsConfig } from '@zerly/eslint-config';

export default [
  ...nx.configs['flat/base'],
  ...nx.configs['flat/typescript'],
  ...nx.configs['flat/javascript'],

  {
    files: ['**/*.json'],
    languageOptions: { parser: jsoncParser },
    plugins: { '@nx': nx },
    rules: {
      '@nx/dependency-checks': ['error', { /* your options */ }],
    },
  },

  {
    files: ['**/*.ts', '**/*.tsx', '**/*.js', '**/*.jsx'],
    plugins: { '@nx': nx },
    rules: {
      '@nx/enforce-module-boundaries': ['error', { /* your options */ }],
    },
  },

  ...defineNestjsConfig({ tsconfigRootDir: import.meta.dirname }),
];

Options

interface ITypescriptConfigOptions {
  /**
   * Absolute path to the directory containing `tsconfig.base.json`.
   * Pass `import.meta.dirname` from your root ESLint config.
   */
  tsconfigRootDir: string;
}

Individual configs

For fine-grained control, each config layer is exported separately:

import {
  baseConfig,       // common JS/TS rules
  typescriptConfig, // type-aware @typescript-eslint rules
  jsdocConfig,      // JSDoc validation
  sonarjsConfig,    // SonarJS recommended
  ignoresConfig,    // default ignores (node_modules, dist, .nx…)
} from '@zerly/eslint-config';

Notable conventions

• Interface prefix — interfaces must be prefixed with I (IUserService, not UserService)
• Explicit accessibility — all class members require explicit public/private/protected
• No floating promises — unhandled promises are errors; use void to explicitly ignore
• No floating observables — RxJS observables must be subscribed, returned, or marked void
• node: protocol — all Node.js built-in imports must use the explicit node: prefix
• return await in try/catch — required so rejections are caught by the surrounding block