addlicense-ts

A TypeScript port of Google's addlicense — adds copyright license headers to source code files.

Installation

npm install -g addlicense-ts

Or use directly with npx:

npx addlicense-ts <pattern...>

Usage

addlicense-ts <pattern...> [options]

Arguments

• <pattern...> — File or directory patterns to scan (e.g., src/**/*.ts)

Options

| Flag | Description | Default | |------|-------------|---------| | -c, --copyright <holder> | Copyright holder name | Google LLC | | -l, --license <type> | License type: apache, bsd, mit, mpl | apache | | -f, --license-file <file> | Path to a custom license file | — | | -y, --year <year> | Copyright year(s) | Current year | | -v, --verbose | Print names of modified or skipped files | false | | -C, --check | Check-only mode: exit non-zero if headers are missing | false | | -s, --spdx <mode> | SPDX identifier mode: only, top, replace | off | | -i, --ignore <pattern> | Ignore pattern (repeatable) | [] | | -S, --skip <ext> | File extension to skip (repeatable) | [] | | -h, --help | Display help | — |

Examples

Add Apache 2.0 headers to all TypeScript files:

addlicense-ts "src/**/*.ts" -c "Acme Inc."

Check if all files have headers (CI-friendly):

addlicense-ts "src/**/*.ts" --check

Use MIT license with a custom year range:

addlicense-ts "src/**/*.ts" -l mit -y "2020-2025" -c "Jane Doe"

Add SPDX identifiers only:

addlicense-ts "src/**/*.ts" -s only

Ignore node_modules and test files:

addlicense-ts "**/*.ts" -i "node_modules/**" -i "**/*.test.ts"

Supported Licenses

• Apache 2.0 (apache)
• BSD 3-Clause (bsd)
• MIT (mit)
• Mozilla Public License 2.0 (mpl)

Supported File Types

The tool automatically detects the correct comment style for supported file types, including:

• JavaScript / TypeScript (//)
• Python / Ruby / Shell (#)
• HTML / XML / SVG (<!-- -->)
• CSS / SCSS (/* */)
• C / C++ / Go / Java / Rust (/* */ or //)
• And many more

Programmatic API

import { run, type Options } from "addlicense-ts";

const options: Options = {
  patterns: ["src/**/*.ts"],
  holder: "Acme Inc.",
  license: "mit",
  year: "2025",
  verbose: false,
  check: false,
  spdx: 0, // SpdxMode.Off
  ignore: [],
  skip: [],
  licenseFile: "",
};

await run(options);

Development

# Install dependencies
pnpm install

# Build
pnpm run build

# Run tests
pnpm run test

# Run tests with coverage
pnpm run test:cov

# Lint
pnpm run lint

# Format
pnpm run lint:format

# Type check
pnpm run lint:tsc

License

MIT