How to fix Project reference 'X' does not exist in TypeScript

# Check if the directory exists
ls -la path/to/referenced/project

# Check if tsconfig.json exists in that directory
ls -la path/to/referenced/project/tsconfig.json

# View the tsconfig.json to verify it's valid JSON
cat path/to/referenced/project/tsconfig.json | head -20

{
  "references": [
    { "path": "../shared" },           // Points to directory with tsconfig.json
    { "path": "../utils/tsconfig.json" } // Points directly to config file
  ]
}

// In the referenced project's tsconfig.json
{
  "compilerOptions": {
    "composite": true,          // REQUIRED for project references
    "declaration": true,        // REQUIRED - generates .d.ts files
    "declarationMap": true,     // Optional but recommended
    "rootDir": "./src",         // Should be set explicitly
    "outDir": "./dist"          // Should be set explicitly
  },
  "include": ["src/**/*"],
  "exclude": ["node_modules", "dist"]
}

# Navigate to the referenced project directory
cd path/to/referenced/project

# Build it using TypeScript's build mode
npx tsc --build
# or
npx tsc -b

# Alternatively, build from the root using the project reference
cd /path/to/root
npx tsc --build --verbose

# Look for .d.ts files in the output directory
ls -la path/to/referenced/project/dist/*.d.ts

# If using a different outDir, check there
ls -la path/to/referenced/project/build/*.d.ts

// WRONG - incorrect path syntax
{
  "references": [
    { "path": "./shared" },           // Should be "../shared" if up one level
    { "path": "utils/" },             // Missing "./" prefix
    { "path": "../SHARED" },          // Wrong case on case-sensitive systems
    { "path": "../shared\" },        // Wrong slash direction (Windows)
  ]
}

// CORRECT - proper path syntax
{
  "references": [
    { "path": "../shared" },          // Relative path to sibling directory
    { "path": "./packages/utils" },   // Relative path to subdirectory
    { "path": "/absolute/path/to/project" }, // Absolute path (not recommended)
    { "path": "../lib/tsconfig.lib.json" } // Direct config file reference
  ]
}

# Visualize project dependencies
npx tsc --build --dry --verbose

# This will show the build order and detect cycles

Project A references Project B
Project B references Project C
Project C references Project A  // Circular!

# Build projects in correct order manually
npx tsc -b packages/core      # Build core first
npx tsc -b packages/shared    # Then shared (depends on core)
npx tsc -b packages/app       # Finally app (depends on both)

// tsconfig.json at root (solution file)
{
  "files": [],
  "references": [
    { "path": "./packages/core" },
    { "path": "./packages/shared" },
    { "path": "./packages/app" }
  ]
}

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

# Or manually remove build artifacts
rm -rf */dist */build */.tsbuildinfo
rm -rf node_modules/.cache/tsc

# Rebuild everything
npx tsc --build --force

# For monorepos with npm/yarn workspaces
npm run clean:all
npm run build:all

# With Lerna
npx lerna run clean
npx lerna run build

# With Nx
npx nx run-many --target=build --all

# With Turborepo
npx turbo clean
npx turbo build