How to fix Project reference is stale, run 'tsc --build' in TypeScript

# Rebuild all projects in the solution
tsc --build

# Or with shorter syntax
tsc -b

# If you have a specific tsconfig.json for building
tsc --build tsconfig.json

# For incremental builds (faster)
tsc --build --incremental

# Clean all build outputs
tsc --build --clean

# Then rebuild
tsc --build

# Or combine in one command
tsc --build --clean --force

// tsconfig.json (root or main project)
{
  "compilerOptions": {
    "composite": true,
    "declaration": true,
    "declarationMap": true,
    "outDir": "./dist"
  },
  "references": [
    { "path": "./packages/core" },
    { "path": "./packages/utils" }
  ]
}

// packages/core/tsconfig.json
{
  "compilerOptions": {
    "composite": true,
    "declaration": true,
    "declarationMap": true,
    "outDir": "../../dist/core"
  }
}

// packages/utils/tsconfig.json
{
  "compilerOptions": {
    "composite": true,
    "declaration": true,
    "declarationMap": true,
    "outDir": "../../dist/utils"
  }
}

// package.json
{
  "scripts": {
    "build": "tsc --build",
    "build:clean": "tsc --build --clean",
    "build:watch": "tsc --build --watch",
    "build:incremental": "tsc --build --incremental",
    "clean": "tsc --build --clean"
  }
}

npm run build        # Standard build
npm run build:watch  # Watch mode for development
npm run clean        # Clean build artifacts

{
  "scripts": {
    "build": "npm run build --workspaces",
    "build:packages": "npm run build --workspace=packages/*"
  }
}

// WRONG - missing composite
{
  "compilerOptions": {
    "declaration": true
  }
}

// CORRECT
{
  "compilerOptions": {
    "composite": true,
    "declaration": true
  }
}

// WRONG - projects output to same directory
{
  "compilerOptions": {
    "outDir": "../dist"
  }
}

// CORRECT - unique output directories
{
  "compilerOptions": {
    "outDir": "../dist/core"
  }
}

// WRONG - references tsconfig.json file directly
{
  "references": [
    { "path": "./packages/core/tsconfig.json" }
  ]
}

// CORRECT - references directory
{
  "references": [
    { "path": "./packages/core" }
  ]
}

# Watch all projects
tsc --build --watch

# Watch with specific tsconfig
tsc --build tsconfig.json --watch

# Watch with incremental builds
tsc --build --watch --incremental

# In package.json scripts
{
  "scripts": {
    "dev": "tsc --build --watch",
    "dev:incremental": "tsc --build --watch --incremental"
  }
}