NestJS + Next.js /4 Folder structure & config

.eslintrc.js

// src/client/.eslintrc.js
// Your custom ESLint file for React, applied only to src/client automatically

module.exports = {
  parser: '@typescript-eslint/parser',
  parserOptions: {
    project: 'src/client/tsconfig.json',
    sourceType: 'module',
  },
  plugins: ['@typescript-eslint/eslint-plugin'],
  extends: [
    'plugin:@typescript-eslint/recommended',
    'prettier/@typescript-eslint',
    'plugin:prettier/recommended',
  ],
  root: true,
  env: {
    jest: true,
  },
  ignorePatterns: ['.eslintrc.js'],
  rules: {
    '@typescript-eslint/interface-name-prefix': 'off',
    '@typescript-eslint/explicit-function-return-type': 'off',
    '@typescript-eslint/explicit-module-boundary-types': 'off',
    '@typescript-eslint/no-explicit-any': 'off',
    '@typescript-eslint/no-unused-vars': ['warn', { 'argsIgnorePattern': '^_' }]
  },
};

nest-cli.json

// nest-cli.json

{
  "sourceRoot": "src/server"
}

next-env.d.ts

/// <reference types="next" />
/// <reference types="next/types/global" />

// ^ Put this in src/client/next-env.d.ts

next.config.js

// Put this in src/client/next.config.js
// This is so .next folder is in the root directory. Make sure to add .next to .gitignore

module.exports = {
  distDir: '../../.next',
};

package.json

// package.json

{
  "scripts": {
    "build": "nest build && cd src/client && next build",
  }
}

root-tsconfig.json

// Edit your Nest TypeScript config in the root dir (tsconfig.json) to only apply to the server code
{
  "include": ["src/server"],
}

tsconfig.json

// Your custom TypeScript config for React, applied only to src/client automatically
// Put this in src/client/tsconfig.json 

{
  "compilerOptions": {
    "target": "es5",
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ],
    "allowJs": true,
    "skipLibCheck": true,
    "strict": false,
    "forceConsistentCasingInFileNames": true,
    "noEmit": true,
    "esModuleInterop": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "jsx": "preserve"
  },
  "include": [
    "next-env.d.ts",
    "next.config.js",
    "pages/**/*.ts",
    "pages/**/*.tsx"
  ],
  "exclude": [
    "node_modules"
  ]
}