How to fix The 'include' pattern is empty or matches no files in TypeScript

{
  "compilerOptions": {
    // ... other options
  },
  "include": ["src/**/*", "tests/**/*"],
  "exclude": ["node_modules", "dist"]
}

# Check if src directory exists
ls -la src/

# Check what files are in src
find src -name "*.ts" -o -name "*.tsx" | head -10

// WRONG - src directory doesn't exist
{
  "include": ["src/**/*"]
}

// CORRECT - use actual directory name
{
  "include": ["lib/**/*"]
}

// If using multiple source directories:
{
  "include": ["packages/**/*", "apps/**/*", "shared/**/*"]
}

// If source files are in root directory:
{
  "include": ["**/*.ts", "**/*.tsx"]
}

# Show directory structure
tree -I 'node_modules|dist|build' -L 3

# Or with find
find . -type f -name "*.ts" -o -name "*.tsx" | grep -v node_modules | head -20

// Default extensions TypeScript looks for:
// .ts, .tsx, .d.ts
// .js and .jsx if allowJs is true

// WRONG - looking for .typescript files
{
  "include": ["**/*.typescript"]
}

// CORRECT - looking for .ts files
{
  "include": ["**/*.ts"]
}

// Include both .ts and .tsx
{
  "include": ["**/*.{ts,tsx}"]
}

// Include JavaScript files too
{
  "compilerOptions": {
    "allowJs": true
  },
  "include": ["**/*.{ts,tsx,js,jsx}"]
}

# Count files by extension
find . -type f -name "*.ts" | wc -l
find . -type f -name "*.tsx" | wc -l
find . -type f -name "*.js" | wc -l
find . -type f -name "*.jsx" | wc -l

// Using files array (explicit file listing)
{
  "compilerOptions": {
    // ... options
  },
  "files": [
    "src/index.ts",
    "src/utils/helpers.ts",
    "src/types/index.d.ts"
  ]
}

// Mixed approach - include patterns plus specific files
{
  "include": ["src/**/*"],
  "files": [
    "global.d.ts",  // Always include this
    "types/custom.d.ts"  // And this
  ]
}

// When both files and include are specified:
// - files are always included
// - include patterns add additional files
// - exclude still applies to include patterns

// WRONG - exclude pattern removes everything
{
  "include": ["src/**/*"],
  "exclude": ["src"]  // Excludes entire src directory!
}

// CORRECT - exclude specific subdirectories
{
  "include": ["src/**/*"],
  "exclude": ["src/**/*.test.ts", "src/**/*.spec.ts"]
}

// WRONG - exclude uses wildcard that matches everything
{
  "include": ["**/*.ts"],
  "exclude": ["**/*"]  // Excludes all files!
}

// CORRECT - exclude node_modules and build outputs
{
  "include": ["**/*.ts"],
  "exclude": ["node_modules", "dist", "build", "coverage"]
}

# Create a test to see what files match
npx tsc --listFiles | head -20

# Or compile with verbose output
npx tsc --extendedDiagnostics

// Base tsconfig.json
{
  "compilerOptions": {
    "strict": true
  },
  "include": ["src/**/*"]
}

// tsconfig.build.json (extends base)
{
  "extends": "./tsconfig.json",
  "include": ["src/**/*"],  // This OVERRIDES parent include!
  "exclude": ["**/*.test.ts", "**/*.spec.ts"]
}

// When using extends:
// - compilerOptions are merged
// - include/exclude/files REPLACE parent values (not merged)
// - Last config in chain wins

// Common mistake - empty include in child config
{
  "extends": "./tsconfig.json",
  "include": [],  // Overrides parent with empty array!
  "exclude": ["tests"]
}

# Default uses tsconfig.json
npx tsc

# Specify config file
npx tsc -p tsconfig.build.json

# Check current directory
pwd
ls -la tsconfig*.json