License Scanning

/**
 * Initialize license scanning for a given directory
 * @param options - Configuration options for the scan
 * @param callback - Callback function receiving results or errors
 */
function init(options: ScanOptions, callback: (err: Error | null, data: LicenseData) => void): void;

interface ScanOptions {
  /** Directory to start scanning from (default: process.cwd()) */
  start?: string;
  /** Only include production dependencies */
  production?: boolean;
  /** Only include development dependencies */
  development?: boolean;
  /** Report guessed licenses as unknown */
  unknown?: boolean;
  /** Only list packages with unknown or guessed licenses */
  onlyunknown?: boolean;
  /** Look for direct dependencies only (not transitive) */
  direct?: boolean;
  /** Custom output format specification */
  customFormat?: CustomFormat;
  /** Path to custom format JSON file */
  customPath?: string;
  /** Comma-separated list of licenses to exclude from output */
  exclude?: string;
  /** Semicolon-separated list of licenses that cause failure (exit code 1) */
  failOn?: string;
  /** Semicolon-separated list of only allowed licenses (others cause failure) */
  onlyAllow?: string;
  /** Semicolon-separated list of specific packages to include */
  packages?: string;
  /** Semicolon-separated list of packages to exclude */
  excludePackages?: string;
  /** Exclude packages marked as private */
  excludePrivatePackages?: boolean;
  /** Output license file paths as relative to base path */
  relativeLicensePath?: boolean;
  /** Enable colored output for terminal display */
  color?: boolean;
}

const checker = require("license-checker");

// Basic scan of current directory
checker.init({
  start: process.cwd()
}, function(err, packages) {
  if (err) {
    console.error("Error:", err);
  } else {
    console.log("Found", Object.keys(packages).length, "packages");
    console.log(packages);
  }
});

// Production dependencies only with custom format
checker.init({
  start: "./my-project",
  production: true,
  customFormat: {
    name: "",
    version: "",
    licenses: "",
    repository: ""
  }
}, function(err, packages) {
  if (err) throw err;
  Object.keys(packages).forEach(key => {
    const pkg = packages[key];
    console.log(`${pkg.name}@${pkg.version}: ${pkg.licenses}`);
  });
});

// Exclude specific licenses
checker.init({
  start: process.cwd(),
  exclude: "MIT,ISC,BSD-3-Clause"
}, function(err, packages) {
  // Only packages NOT licensed under MIT, ISC, or BSD-3-Clause
  console.log(packages);
});

// Fail on GPL licenses
checker.init({
  start: process.cwd(),
  failOn: "GPL-2.0;GPL-3.0;LGPL-2.1"
}, function(err, packages) {
  // Process will exit with code 1 if any GPL licenses found
  console.log(packages);
});

// Only allow specific licenses
checker.init({
  start: process.cwd(),
  onlyAllow: "MIT;Apache-2.0;BSD-3-Clause"
}, function(err, packages) {
  // Process will exit with code 1 if any other licenses found
  console.log(packages);
});

interface LicenseData {
  [packageKey: string]: PackageInfo;
}

interface PackageInfo {
  /** License identifier(s) - string for single license, array for multiple */
  licenses: string | string[];
  /** Git repository URL (normalized from various formats) */
  repository?: string;
  /** Package author/publisher name */
  publisher?: string;
  /** Author email address */
  email?: string;
  /** Author or package homepage URL */
  url?: string;
  /** Local filesystem path to the package */
  path?: string;
  /** Path to the license file (absolute or relative based on options) */
  licenseFile?: string;
  /** Full text content of the license file */
  licenseText?: string;
  /** Extracted copyright statements from license files */
  copyright?: string;
  /** Path to NOTICE file if present */
  noticeFile?: string;
  /** Whether the package is marked as private */
  private?: boolean;
  /** Dependency path information (when unknown option is enabled) */
  dependencyPath?: string;
}

{
  "license-checker@25.0.1": {
    "licenses": "BSD-3-Clause",
    "repository": "https://github.com/davglass/license-checker",
    "publisher": "Dav Glass",
    "email": "davglass@gmail.com",
    "path": "/path/to/node_modules/license-checker",
    "licenseFile": "/path/to/node_modules/license-checker/LICENSE"
  },
  "chalk@2.4.2": {
    "licenses": "MIT",
    "repository": "https://github.com/chalk/chalk",
    "publisher": "Sindre Sorhus",
    "email": "sindresorhus@gmail.com",
    "url": "sindresorhus.com",
    "path": "/path/to/node_modules/chalk",
    "licenseFile": "/path/to/node_modules/chalk/license"
  }
}

checker.init({
  start: process.cwd(),
  customFormat: {
    "name": "",              // Extract package name
    "version": "",           // Extract package version  
    "description": "",       // Extract package description
    "homepage": "",          // Extract homepage URL
    "author": "",           // Extract author information
    "keywords": [],         // Extract keywords array
    "licenseText": false,   // Include full license text
    "copyright": false      // Include copyright extraction
  }
}, callback);