@lizenz/checker

@lizenz/checker extracts license information from the installed dependency tree of an npm project. It is an ESM-only TypeScript port of license-checker-rseidelsohn at the frozen upstream commit fa55e1197.

Command line

The primary command is license-checker. Existing scripts can keep using the compatibility alias license-checker-rseidelsohn (for now).

All CLI options in alphabetical order:

• --clarificationsFile: read package-specific license clarifications from a JSON file.
• --clarificationsMatchAll: fail if any clarification entry was not used.
• --color: colorize terminal tree output.
• --csv: output CSV.
• --csvComponentPrefix: add a component column prefix to CSV output.
• --customPath: read a custom output format from a JSON file.
• --depth: recurse through the specified number of dependency levels and override the direct setting.
• --development: include only development dependencies.
• --excludeLicenses: exclude a comma-separated list of licenses.
• --excludePackages: exclude a semicolon-separated list of package selectors.
• --excludePackagesStartingWith: exclude packages with semicolon-separated prefixes.
• --excludePrivatePackages: exclude packages marked private.
• --failOn: fail on a semicolon-separated list of licenses.
• --files: copy discovered license files to a directory.
• --help (-h): print usage information.
• --includeLicenses: include only a comma-separated list of licenses.
• --includePackages: include only a semicolon-separated list of package selectors.
• --json: output formatted JSON.
• --limitAttributes: restrict JSON output to a comma-separated list of fields.
• --markdown: output Markdown.
• --nopeer: skip peer dependencies.
• --onlyAllow: fail on licenses outside a semicolon-separated allow-list.
• --onlyunknown: list only unknown or guessed licenses.
• --out: write formatted output to a file.
• --plainVertical: output license text in plain vertical format.
• --production: include only production dependencies.
• --relativeLicensePath: make license-file paths relative.
• --relativeModulePath: make module paths relative.
• --start: set the project path to scan.
• --summary: output license counts.
• --unknown: report guessed licenses as unknown.
• --version (-v): print the package version using the historic CLI exit behavior.

Deprecated CLI options that still work, but will be removed in the future to reduce clutter and simplify usage:

• --angularCli: synonym for the plain vertical output mode; the frozen compatibility baseline retains its historic behavior.
• --direct: retain the historic direct/depth normalization behavior.

When several output flags are present, precedence is JSON, CSV, Markdown, Summary, Plain Vertical, then Tree.

Programmatic API

import { runLicenseCheck } from '@lizenz/checker';

const modules = await runLicenseCheck({ start: process.cwd() });

runLicenseCheck returns a promise and never terminates the host process. Policy, clarification, input, and file-system errors reject that promise. The deprecated callback-based init wrapper remains available for compatibility with the upstream API; new code should use runLicenseCheck.

Debugging

Use the namespaces @lizenz/checker:error and @lizenz/checker:log with the DEBUG environment variable.

License and upstream

This package is distributed under the BSD 3-Clause License. It derives from the original license-checker work by Dav Glass and the enhanced license-checker-rseidelsohn maintained by Roman Seidelsohn and Roland Hummel.