license-checker-rseidelsohn

NPM License Checker

Table of Contents

• A message from the maintainer
• Introduction
• Changes
• All options in alphabetical order
• Exclusions
• Examples
• Clarifications
• Custom format
• Requiring
• Debugging
• How Licenses are Found
• Related information sources on the internet

A message from the maintainer

Folks, I love and honor open software (the latter not as much as I should), and therefore I am a little ashamed of the lack of regular care I give to this project. My family (two still young kids and a wife working full-time just as me) plus my hobbies (reading - currently I read the great book "Coders at work" and plan to work my way through "Structure and interpretation of computer programs", a book many great and experienced coders say is kind of a must-read - and homebrewing) take their toll. And then there's the time I need for procrastination as well. You get the picture.

I took over this project from another guy who initially built it, because he did not respond to any PRs or emails for years and I needed a feature that was not available. And I thought there are enough people out there that should profit from what I do, so I forked the license-checker under the now pretty clumsy name license-checker-rseidelsohn - here we are.

I am always happy when I see PR's being created by other coders out there or if someone writes me an email - no matter what it might be about. Just the feeling that this tool and what I do with it does not only live in the void is already amazing to me. This being said, I am really looking for more people that want to contribute, so feel free if you want to be added as maintainers.

But also, I am now working for Springer Nature since mid of February, and this awesome employer (I can only and absolutely recommend working for Springer Nature, and I get no advantages whatsoever through this message - they don't even know about it!) gives their devs a 10% Friday every 2nd Friday, where the devs are not disturbed by any meetings and are free to work on whatever they wish (preferrably anything that helps improve their skills and/or the codebase), and I plan to take this open source project and maintain it during that time. So I would like to give you hope that the updates will come more frequently and in better quality.

Berlin, 1st of April 2023.

Introduction

This is a fork of davglass' license-checker v.25.0.1 - Since that code doesn't seem to be updated regularly, I created this fork for being able to adding new features and fixing bugs.

I changed the original exclude argument to excludeLicenses in order to prevent confusion and better align it with the excludePackages argument. Also, the argument includeLicenses has been added for listing only packages that include the licenses listed.

Please notice: Version 1.2.2 is the last version working fine on node v12. From Version 2 on, you will need at least Node v14 to run this NPM license checker. Thanks to @daniel-schulz for pointing this out!

Ever needed to see all the license info for a module and its dependencies?

It's this easy:

npm install -g license-checker-rseidelsohn

mkdir foo
cd foo
npm install yui-lint
license-checker-rseidelsohn

You should see something like this:

├─ cli@0.4.3
│  ├─ repository: http://github.com/chriso/cli
│  └─ licenses: MIT
├─ debug@2.0.0
│  ├─ repository: https://github.com/visionmedia/debug
│  └─ licenses: MIT*
├─ glob@3.1.14
│  ├─ repository: https://github.com/isaacs/node-glob
│  └─ licenses: UNKNOWN
├─ graceful-fs@1.1.14
│  ├─ repository: https://github.com/isaacs/node-graceful-fs
│  └─ licenses: UNKNOWN
├─ inherits@1.0.0
│  ├─ repository: https://github.com/isaacs/inherits
│  └─ licenses: UNKNOWN
├─ jshint@0.9.1
│  └─ licenses: MIT
├─ lru-cache@1.0.6
│  ├─ repository: https://github.com/isaacs/node-lru-cache
│  └─ licenses: MIT
├─ lru-cache@2.0.4
│  ├─ repository: https://github.com/isaacs/node-lru-cache
│  └─ licenses: MIT
├─ minimatch@0.0.5
│  ├─ repository: https://github.com/isaacs/minimatch
│  └─ licenses: MIT
├─ minimatch@0.2.9
│  ├─ repository: https://github.com/isaacs/minimatch
│  └─ licenses: MIT
├─ sigmund@1.0.0
│  ├─ repository: https://github.com/isaacs/sigmund
│  └─ licenses: UNKNOWN
└─ yui-lint@0.1.1
   ├─ licenses: BSD
   └─ repository: http://github.com/yui/yui-lint

An asterisk next to a license name means that it was deduced from another file than package.json (README, LICENSE, COPYING, ...).

Changes

Take a look at the detailed changelog or at the releases page.

All options in alphabetical order

• --angularCli is just a synonym for --plainVertical
• --clarificationsFile [filepath] A file that describe the license clarifications for each package. See clarificationExample.json. Any field available to the customFormat option can be clarified. The clarifications file can also be used to specify a subregion of a package's license file (instead of reading the entire file)
• --clarificationsMatchAll [boolean] This optional new feature is still lacking a description - to be done
• --csv output in csv format
• --csvComponentPrefix prefix column for component in csv format
• --customPath to add a custom Format file in JSON
• --depth [number] look for "number" of levels of dependencies - overrides the ambiguously named "--direct" option
• --development only show development dependencies.
• --direct [boolean|number] look for direct dependencies only if "true" or look for "number" of levels of dependencies
• --excludeLicenses [list] exclude modules which licenses are in the comma-separated list from the output
• --excludePackages [list] restrict output to the packages (either "package@fullversion" or "package@majorversion" or only "package") not in the semicolon-separated list
• --excludePackagesStartingWith [list] exclude modules which names start with the comma-separated list from the output (useful for excluding modules from a specific vendor and such). Example: --excludePackagesStartingWith "webpack;@types;@babel"
• --excludePrivatePackages restrict output to not include any package marked as private
• --failOn [list] fail (exit with code 1) on the first occurrence of the licenses of the semicolon-separated list
• --files [path] copy all license files to path and rename them to module-name@version-LICENSE.txt
• --includeLicenses [list] include only modules which licenses are in the comma-separated list from the output
• --includePackages [list] restrict output to the packages (either "package@fullversion" or "package@majorversion" or only "package") in the semicolon-separated list
• --json output in json format
• --limitAttributes [list] limit the attributes to be output
• --markdown output in markdown format
• --nopeer skip peer dependencies in output
• --onlyAllow [list] fail (exit code 1) on the first occurrence of the licenses not in the semicolon-separated list
• --onlyunknown only list packages with unknown or guessed licenses
• --out [filepath] write the data to a specific file
• --plainVertical output license info in plain vertical format like Angular CLI does
• --production only show production dependencies.
• --relativeLicensePath output the location of the license files as relative paths
• --relativeModulePath output the location of the module files as relative paths
• --start [filepath] path of the initial JSON to look for
• --summary output a summary of the license usage
• --unknown report guessed licenses as unknown licenses
• --version The current version
• --help The text you are reading right now :)

Exclusions

A list of licenses is the simplest way to describe what you want to exclude.

You can use valid SPDX identifiers. You can use valid SPDX expressions like MIT OR X11.

You can use non-valid SPDX identifiers, like Public Domain, since npm does support some license strings that are not SPDX identifiers.

Examples

license-checker-rseidelsohn --json > /path/to/licenses.json
license-checker-rseidelsohn --csv --out /path/to/licenses.csv
license-checker-rseidelsohn --unknown
license-checker-rseidelsohn --customPath customFormatExample.json
license-checker-rseidelsohn --excludeLicenses 'MIT, MIT OR X11, BSD, ISC'
license-checker-rseidelsohn --includePackages 'react@16.3.0;react-dom@16.3.0;lodash@4.3.1'
license-checker-rseidelsohn --excludePackages 'internal-1;internal-2'
license-checker-rseidelsohn --onlyunknown

Clarifications

The --clarificationsFile option can be used to provide custom processing instructions on a per-package basis. The format is as so:

{
    "package_name@version": {
        // Any field available in customFormat can be clarified
        "licenses": "MIT",
        "licenseFile": "some/path",
        "licenseText": "The full text of the license to include if you need",
        // You can optionally add a SH-256 checksum of the license file contents that will be checked on each run.
        // Intended to help detect when projects change their license.
        "checksum": "deadbeef...",
        // Add a licenseStart and optional licenseEnd to snip out a substring of the licenseText. The licenseStart will
        // be included in the licenseText, the licenseEnd will not be.
        "licenseStart": "# MIT License",
        "licenseEnd": "=========",
    }
}

version can either be an exact version or a semver range, multiple ranges are supported for a single package, for example:

{
    "package_name@^1": {
        // Any field available in customFormat can be clarified
        "licenses": "GPL",
        // ... other fields, see above
    },
    "package_name@^2": {
        // Any field available in customFormat can be clarified
        "licenses": "MIT",
        // ... other fields, see above
    },
}

For overlapping ranges, the first matching entry is used.

The --clarificationsMatchAll option, when enabled, raises an error if not all specified clarifications were used, it is off by default.

Custom format

The --customPath option can be used with CSV to specify the columns. Note that the first column, module_name, will always be used.

When used with JSON format, it will add the specified items to the usual ones.

The available items are the following:

• copyright
• description
• email
• licenseFile
• licenseModified
• licenses
• licenseText
• name
• publisher
• repository
• url
• version

You can also give default values for each item. See an example in customFormatExample.json.

Note that outputting the license text is not recommended with Markdown formatting, as it can be very long and does not work well with Markdown lists.

Requiring

var checker = require('license-checker-rseidelsohn');

checker.init(
    {
        start: '/path/to/start/looking',
    },
    function (err, packages) {
        if (err) {
            //Handle error
        } else {
            //The sorted package data
            //as an Object
        }
    },
);

Debugging

license-checker uses debug for internal logging. There’s two internal markers:

• license-checker-rseidelsohn:error for errors
• license-checker-rseidelsohn:log for non-errors

Set the DEBUG environment variable to one of these to see debug output:

$ export DEBUG=license-checker-rseidelsohn*; license-checker-rseidelsohn
scanning ./yui-lint
├─ cli@0.4.3
│  ├─ repository: http://github.com/chriso/cli
│  └─ licenses: MIT
# ...

How Licenses are Found

We read the installed node_modules dependency tree with npm's @npmcli/arborist module. Once we gathered a list of modules we walk through them and look at all of their package.json's, We try to identify the license with the spdx module to see if it has a valid SPDX license attached. If that fails, we then look into the module for the following files: LICENSE, LICENCE, COPYING, & README.

If one of the those files are found (in that order) we will attempt to parse the license data from it with a list of known license texts. This will be shown with the * next to the name of the license to show that we "guessed" at it.

Related information sources on the internet

• ChooseALicense.com aims at helping you in choosing an open source license for your project
• TLDRLegal.com aims at explaining complicated legal details of software licenses in easy to understand English