Add ESLint and Prettier configuration across monorepo

Co-authored-by: PatrickFanella <61631520+PatrickFanella@users.noreply.github.com>

.eslintrc.json

@@ -0,0 +1,39 @@
+{
+  "root": true,
+  "env": {
+    "node": true,
+    "es2022": true
+  },
+  "parser": "@typescript-eslint/parser",
+  "parserOptions": {
+    "ecmaVersion": 2022,
+    "sourceType": "module",
+    "project": "./tsconfig.json"
+  },
+  "extends": [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/recommended",
+    "prettier"
+  ],
+  "plugins": ["@typescript-eslint"],
+  "rules": {
+    "@typescript-eslint/no-explicit-any": "warn",
+    "@typescript-eslint/no-unused-vars": [
+      "warn",
+      {
+        "argsIgnorePattern": "^_",
+        "varsIgnorePattern": "^_"
+      }
+    ]
+  },
+  "ignorePatterns": [
+    "node_modules/",
+    "dist/",
+    "cache/",
+    "artifacts/",
+    "typechain-types/",
+    "coverage/",
+    ".nyc_output/",
+    "web/"
+  ]
+}

.gitignore

@@ -54,6 +54,9 @@ lerna-debug.log*
 .vscode/
 .idea/
 
+# Linting
+.eslintcache
+
 # Next.js (applies to any package path)
 .next/
 out/

.prettierignore

@@ -0,0 +1,14 @@
+node_modules/
+dist/
+cache/
+artifacts/
+typechain-types/
+coverage/
+.nyc_output/
+.next/
+out/
+.vercel/
+package-lock.json
+*.log
+*.db
+*.sqlite

.prettierrc.json

@@ -0,0 +1,10 @@
+{
+  "semi": true,
+  "trailingComma": "es5",
+  "singleQuote": false,
+  "printWidth": 100,
+  "tabWidth": 2,
+  "useTabs": false,
+  "arrowParens": "always",
+  "endOfLine": "lf"
+}

README.md

@@ -34,6 +34,43 @@ This project implements comprehensive input validation and sanitization to preve
 
 All API endpoints validate inputs against strict schemas with detailed error messages. See [docs/VALIDATION.md](./docs/VALIDATION.md) for complete documentation.
 
+## Code Quality
+
+This project uses ESLint and Prettier to maintain consistent code style and catch common issues:
+
+- **ESLint**: Configured for both Node.js/Hardhat scripts (TypeScript) and Next.js app
+- **Prettier**: Shared formatting config across the monorepo
+
+### Linting & Formatting
+
+```bash
+# Run linters across the entire monorepo
+npm run lint
+
+# Fix auto-fixable linting issues
+npm run lint:fix
+
+# Format all code with Prettier
+npm run format
+
+# Check if code is properly formatted
+npm run format:check
+```
+
+For the web package specifically:
+
+```bash
+cd web
+npm run lint        # ESLint for Next.js app
+npm run lint:fix    # Auto-fix issues
+npm run format      # Format with Prettier
+```
+
+Configuration files:
+- Root ESLint: `.eslintrc.json` (TypeScript + Node.js)
+- Web ESLint: `web/.eslintrc.json` (Next.js)
+- Prettier: `.prettierrc.json` (shared)
+
 ## Setup
 
 1. Install deps
@@ -69,10 +106,17 @@ If you plan to use the included web UI (`web/`), set:
 - `bind:youtube` – bind a YouTube videoId to a previously registered master file
 - `verify:youtube` – verify a YouTube URL/ID via on-chain binding + manifest
 - `start:api` – start the Express API server (default port 3001)
+- `lint` – run ESLint on both root and web packages
+- `lint:fix` – automatically fix ESLint issues where possible
+- `format` – format all code with Prettier
+- `format:check` – check if code is formatted correctly
 - Web: from `web/` workspace
   - `npm run dev` – start Next.js dev server on :3000
   - `npm run build && npm start` – production build/start
   - `npm run prisma:generate` – generate Prisma Client for web (uses root schema)
+  - `npm run lint` – run ESLint on web package
+  - `npm run lint:fix` – automatically fix ESLint issues in web package
+  - `npm run format` – format web code with Prettier
 
 ## Quickstart
 

package.json

@@ -24,7 +24,15 @@
     "db:generate": "prisma generate",
     "db:migrate": "prisma migrate dev --name init",
     "db:studio": "prisma studio",
-    "db:verify-indexes": "ts-node scripts/verify-indexes.ts"
+    "db:verify-indexes": "ts-node scripts/verify-indexes.ts",
+    "lint": "npm run lint:root && npm run lint:web",
+    "lint:root": "eslint . --ext .ts,.js",
+    "lint:web": "cd web && npm run lint",
+    "lint:fix": "npm run lint:fix:root && npm run lint:fix:web",
+    "lint:fix:root": "eslint . --ext .ts,.js --fix",
+    "lint:fix:web": "cd web && npm run lint:fix",
+    "format": "prettier --write \"**/*.{ts,js,json,md}\"",
+    "format:check": "prettier --check \"**/*.{ts,js,json,md}\""
   },
   "devDependencies": {
     "@nomicfoundation/hardhat-chai-matchers": "^2.1.0",
@@ -44,12 +52,18 @@
     "@types/multer": "^1.4.12",
     "@types/node": "^20.12.12",
     "@types/sinon": "^17.0.4",
+    "@typescript-eslint/eslint-plugin": "^6.21.0",
+    "@typescript-eslint/parser": "^6.21.0",
     "chai": "^4.5.0",
     "dotenv": "^16.4.5",
+    "eslint": "^8.57.1",
+    "eslint-config-prettier": "^10.1.8",
+    "eslint-plugin-prettier": "^5.5.4",
     "ethers": "^6.13.3",
     "hardhat": "^2.22.7",
     "hardhat-gas-reporter": "^1.0.10",
     "nyc": "^17.1.0",
+    "prettier": "^3.6.2",
     "prisma": "^6.17.0",
     "sinon": "^21.0.0",
     "solidity-coverage": "^0.8.16",

web/.eslintrc.json

@@ -0,0 +1,8 @@
+{
+  "root": true,
+  "extends": [
+    "next/core-web-vitals",
+    "prettier"
+  ],
+  "rules": {}
+}

web/next.config.mjs

@@ -11,6 +11,13 @@ const nextConfig = {
   turbopack: {
     root: __dirname,
   },
+  // During build, lint but don't fail on pre-existing warnings/errors
+  // This allows gradual ESLint adoption while still catching new issues in CI
+  eslint: {
+    // Warning: This allows production builds to successfully complete even if
+    // your project has ESLint errors. Fix errors and remove this option.
+    ignoreDuringBuilds: true,
+  },
 };
 
 export default nextConfig;

web/package.json

@@ -6,7 +6,10 @@
     "dev": "next dev -p 3000",
     "build": "next build",
     "start": "next start -p 3000",
-    "lint": "next lint",
+    "lint": "eslint . --ext .ts,.tsx,.js,.jsx",
+    "lint:fix": "eslint . --ext .ts,.tsx,.js,.jsx --fix",
+    "format": "prettier --write \"**/*.{ts,tsx,js,jsx,json,md,css}\"",
+    "format:check": "prettier --check \"**/*.{ts,tsx,js,jsx,json,md,css}\"",
     "prisma:generate": "prisma generate --schema ../prisma/schema.prisma --generator client-web",
     "postinstall": "prisma generate --schema ../prisma/schema.prisma --generator client-web"
   },
@@ -26,6 +29,10 @@
     "@types/qrcode": "^1.5.5",
     "@types/react": "18.2.74",
     "@types/react-dom": "18.2.25",
+    "eslint": "^8.57.1",
+    "eslint-config-next": "^15.5.6",
+    "eslint-config-prettier": "^10.1.8",
+    "prettier": "^3.6.2",
     "prisma": "^6.17.0",
     "typescript": "5.6.3"
   }