Setting Up ESLint, Commitlint, Lint-Staged, Husky, and Prettier in a Node.js Application

Learn to set up essential development tools in a Node.js application, including ESLint for code linting, Commitlint for commit message validation, Lint-Staged for running linters on staged files, Husky for Git hooks, and Prettier for code formatting.

Docs:

Implementation:

Install the required dependencies.

npm install -D eslint eslint-plugin-prettier @typescript-eslint/parser @typescript-eslint/eslint-plugin

npm install -D @commitlint/cli @commitlint/config-conventional lint-staged prettier husky

Configure ESLint with a suitable configuration file.

eslint.config.mjs

import tseslint from "@typescript-eslint/eslint-plugin";
import tsparser from "@typescript-eslint/parser";
import prettierPlugin from "eslint-plugin-prettier";
 
export default [
  {
    files: ["**/*.ts"],
 
    ignores: ["node_modules", "dist", "build", "commitlint.config.ts"],
 
    languageOptions: {
      parser: tsparser,
      sourceType: "module"
    },
 
    plugins: {
      "@typescript-eslint": tseslint,
      prettier: prettierPlugin
    },
 
    rules: {
      ...tseslint.configs.recommended.rules,
      "@typescript-eslint/no-unused-vars": "off",
      "@typescript-eslint/no-unused-expressions": "off",
      "no-console": "warn",
      semi: ["error", "always"],
      quotes: ["error", "double"],
      "prettier/prettier": "off"
    }
  }
];

Add the following scripts to your package.json to standardize linting across environments:

package.json

{
  "scripts": {
    "lint:check": "eslint .",
    "lint:fix": "eslint . --fix"
  }
}

Configure Prettier for code formatting.

.prettierrc

{
  "singleQuote": false,
  "semi": true,
  "tabWidth": 2,
  "trailingComma": "none",
  "bracketSameLine": true,
  "arrowParens": "avoid",
  "endOfLine": "lf"
}

Add .prettierignore file.

.prettierignore

node_modules
.next
build
dist
.env
**/*.mdx
**/*.md
coverage

Add the following scripts to your package.json:

package.json

{
  "scripts": {
    "format:check": "npx prettier . --check",
    "format:fix": "npx prettier . --write"
  }
}

Configure Commitlint to validate commit messages.

commitlint.config.ts

export default {
  /**
   * Extends the official Conventional Commits rule set.
   * https://www.conventionalcommits.org/
   */
  extends: ["@commitlint/config-conventional"],
 
  rules: {
 
    "type-enum": [
      2,
      "always",
      [
        "feat",      // New features
        "fix",       // Bug fixes
        "docs",      // Documentation changes only
        "style",     // Formatting, missing semicolons, etc (no logic change)
        "refactor",  // Code restructuring without behavior change
        "test",      // Adding or updating tests
        "chore",     // Tooling, config, or maintenance tasks
        "ci",        // CI/CD configuration changes
        "perf",      // Performance improvements
        "build",     // Build system or dependency changes
        "release",   // Release-related commits
        "workflow",  // GitHub Actions or workflow changes
        "security"   // Security patches and fixes
      ]
    ],
 
    ignores: [(commit: string) => commit === ""],
 
    "body-max-length": [0, "always", 300],
 
    "header-max-length": [0, "always", 100]
  }
};

Set up Lint-Staged to run linters on staged files.

package.json

{
  "scripts": {...},
 
  "lint-staged":{
    "src/**/*.{ts,tsx}": [
      "eslint --fix",
      "prettier --write",
    ],
    "src/**/*.json": [
      "prettier --write"
    ]
  },
 
  "dependencies": {...},
  "devDependencies": {...}
}

Initialize Husky and create Git hooks.

npx husky init

.husky/pre-commit

npx lint-staged

Add a .gitignore file.

.gitignore

# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
 
# dependencies
/node_modules
/.pnp
.pnp.*
.yarn/*
!.yarn/patches
!.yarn/plugins
!.yarn/releases
!.yarn/versions
 
# testing
/coverage
 
# next.js
/.next/
/out/
 
# production
/build
 
# misc
.DS_Store
*.pem
 
# debug
npm-debug.log*
yarn-debug.log*
yarn-error.log*
.pnpm-debug.log*
 
# env files (can opt-in for committing if needed)
.env*
 
# vercel
.vercel
 
# typescript
*.tsbuildinfo
next-env.d.ts

After successfully setting up these tools, your `package.json` should look similar to the following:

package.json

{
  "name": "my-node-app",
  "version": "1.0.0",
  "main": "dist/server.js",
  "type": "module",
  "scripts": {
    "typecheck": "tsc --noEmit",
    "prepare": "husky",
    "lint:check": "eslint .",
    "lint:fix": "eslint . --fix",
    "format:check": "npx prettier . --check",
    "format:fix": "npx prettier . --write"
  },
  "lint-staged": {
    "src/**/*.ts": [
      "eslint --fix",
      "prettier --write",
      "tsc --noEmit"
    ]
  },
  "devDependencies": {
    "@commitlint/cli": "^21.0.1",
    "@commitlint/config-conventional": "^21.0.1",
    "@typescript-eslint/eslint-plugin": "^8.59.4",
    "@typescript-eslint/parser": "^8.59.4",
    "eslint": "^10.4.0",
    "eslint-plugin-prettier": "^5.5.5",
    "husky": "^9.1.7",
    "lint-staged": "^17.0.5",
    "prettier": "^3.8.3",
  }
}

Commands

npm run lint:check

npm run lint:fix

npm run format:check

npm run format:fix

Example

$ git commit -m 'feat: add src/app.ts file'      
✔ Backed up original state in git stash (5ed200a)
✔ Running tasks for staged files...
✔ Staging changes from tasks...
✔ Cleaning up temporary files...
[main d3dc5f3] feat: add src/app.ts file
1 file changed, 7 insertions(+)
create mode 100644 src/app.ts