How to fix Project reference path must point to tsconfig.json in TypeScript

// WRONG - points to directory
{
  "references": [
    { "path": "./packages/shared" },
    { "path": "../utils" }
  ]
}

// CORRECT - points to tsconfig.json file
{
  "references": [
    { "path": "./packages/shared/tsconfig.json" },
    { "path": "../utils/tsconfig.json" }
  ]
}

npx tsc --build
# or
npm run build

# Check if file exists
ls -la ./packages/shared/tsconfig.json

# For Windows PowerShell
Test-Path ./packages/shared/tsconfig.json

# If using a monorepo, check common locations:
find . -name "tsconfig.json" -type f | grep -v node_modules

# Common tsconfig.json naming patterns:
# - tsconfig.json (main)
# - tsconfig.build.json (build-specific)
# - tsconfig.test.json (test-specific)
# - tsconfig.lib.json (library-specific)

{
  "extends": "../../tsconfig.base.json",
  "compilerOptions": {
    "outDir": "./dist"
  },
  "include": ["src/**/*"]
}

// Project structure:
// - tsconfig.json (root)
// - packages/
//   - shared/
//     - tsconfig.json

// WRONG - incorrect relative path
{
  "references": [
    { "path": "packages/shared/tsconfig.json" }  // Missing ./
  ]
}

// CORRECT
{
  "references": [
    { "path": "./packages/shared/tsconfig.json" }
  ]
}

// If using path aliases from baseUrl:
{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "@shared/*": ["packages/shared/src/*"]
    }
  },
  "references": [
    { "path": "./packages/shared/tsconfig.json" }  // Still use file path, not alias
  ]
}

# Check what the path resolves to
node -e "console.log(require('path').resolve(__dirname, './packages/shared/tsconfig.json'))"

# In TypeScript, you can check with:
npx tsc --showConfig

// Root tsconfig.json
{
  "references": [
    { "path": "./packages/shared/tsconfig.json" },
    { "path": "./packages/ui/tsconfig.json" },
    { "path": "./apps/web/tsconfig.json" }
  ]
}

// packages/shared/tsconfig.json
{
  "extends": "../../tsconfig.base.json",
  "compilerOptions": {
    "composite": true,  // Required for project references
    "declaration": true,
    "declarationMap": true,
    "outDir": "./dist"
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist"]
}

# Build all referenced projects
npx tsc --build

# Build specific project
npx tsc --build packages/shared

# Clean builds
npx tsc --build --clean

// package.json
{
  "scripts": {
    "build": "tsc --build",
    "build:watch": "tsc --build --watch",
    "build:clean": "tsc --build --clean",
    "type-check": "tsc --noEmit",

    // For specific projects
    "build:shared": "tsc --build packages/shared",
    "build:ui": "tsc --build packages/ui"
  }
}

# GitHub Actions example
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-node@v3
      - run: npm ci
      - run: npm run build  # Uses tsc --build
      - run: npm test

# 1. Clean previous builds
npx tsc --build --clean

# 2. Build all projects
npx tsc --build

# 3. Check for any remaining errors
npx tsc --noEmit

# 4. Test incremental builds
npx tsc --build --watch &
# Make a change in a referenced project
# Should only rebuild affected projects

# 5. Verify cross-project type checking works
# Create a file that imports from referenced project
echo 'import { something } from "@shared";' > test.ts
npx tsc --noEmit test.ts