Command Line

TypeScript · Reference cheat sheet

📖 Overview

The TypeScript compiler CLI (tsc) type-checks and optionally emits JavaScript. Install via typescript and run with npx tsc or a local node_modules binary. Most options mirror tsconfig.json compiler flags.

🧩 Core concepts

• Project mode — tsc -p tsconfig.json (default: nearest/implicit config).
• Emit vs check — noEmit / --noEmit for CI typecheck; omit for JS output.
• Watch — --watch / -w rebuilds on change.
• Incremental — --incremental + .tsbuildinfo for faster rebuilds.
• Build mode — tsc -b for project references (composite projects).
• Show config — --showConfig prints the effective resolved config.

💡 Examples

# Install
npm install -D typescript
npx tsc --version

# Init a tsconfig
npx tsc --init

# Typecheck only (CI-friendly)
npx tsc -p tsconfig.json --noEmit

# Emit to outDir from config
npx tsc -p tsconfig.json

# Watch mode
npx tsc -p tsconfig.json --watch

# Build solution (project references)
npx tsc -b packages/utils packages/app --force

# One-off compile without relying on config paths
npx tsc src/index.ts --target ES2022 --module NodeNext --outdir dist

# Effective config
npx tsc --showConfig

# Common flags
npx tsc --strict --pretty false --listFiles false

package.json scripts:

{
  "scripts": {
    "typecheck": "tsc -p tsconfig.json --noEmit",
    "build": "tsc -p tsconfig.json"
  }
}

⚠️ Pitfalls

• CLI flags override tsconfig when both are set — know which wins for CI.
• Compiling a single .ts file ignores most of your project paths/include setup.
• tsc -b requires composite: true (and usually declaration: true) on referenced projects.
• Global tsc may be an older version than the project’s local TypeScript — prefer npx/npm exec.

🔗 Related

• Config
• Module
• Types
• Decorators
• Class