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Node License Finder (nlf)

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nlf is a utility for attempting to identify the licenses of modules in a node.js project.

It looks for license information in package.json, readme and license files in the project. Please note, in many cases the utility is looking for standard strings in these files, such as MIT, BSD, Apache, GPL etc - this is not error free, so if you have any concerns at all about the accuracy of the results, you will need to perform a detailed manual review of the project and its dependencies, reading all terms of any included or referenced license.


nlf can be used programmatically, or from the command line.


  • directory (String) - where to look
  • production (Boolean) (Default:false) - only traverse dependencies, no dev-dependencies
  • depth (Number) (Default: Infinity) - how deep to traverse packages where 0 is the current package.json only
  • summaryMode (String: off|simple|detail) (Default: simple)


To install:

$ npm install -g nlf

To use:

cd my-module
$ nlf

Example output:

archy@0.0.2 [license(s): MIT/X11]
└── package.json:  MIT/X11

commander@0.6.1 [license(s): MIT]
└── readme files: MIT

glob@3.2.3 [license(s): BSD]
├── package.json:  BSD
└── license files: BSD

json-stringify-safe@5.0.0 [license(s): BSD]
├── package.json:  BSD
└── license files: BSD

read-installed@0.2.2 [license(s): BSD]
└── license files: BSD

should@1.2.2 [license(s): MIT]
└── readme files: MIT


For output in CSV format use the -c (or --csv) switch:

cd my-module
$ nlf -c

To exclude development dependencies and only analyze dependencies for production:

cd my-module
$ nlf -d

Summary Mode

--summary <mode> option, which can be set to "off", "simple" or "detail". This option controls what will be printed in summary in standard format.

  • off turns off summary output
  • simple shows a list of licenses used in the project, the default behavior
  • detail shows all modules in current project and group by licenses. As example below:
├─┬ BSD
│ ├── amdefine@1.0.0
│ ├── boom@0.4.2
│ ├── cryptiles@0.2.2
│ └── diff@1.4.0
├─┬ BSD-2-Clause
│ └── normalize-package-data@2.3.5
├─┬ Apache-2.0
│ ├── request@2.40.0
│ ├── spdx-correct@1.0.2
│ └── validate-npm-package-license@3.0.1
├─┬ (MIT AND CC-BY-3.0)
│ └── spdx-expression-parse@1.0.1
└─┬ MPL
  └── tough-cookie@2.2.1


var nlf = require('nlf');
nlf.find({ directory: '/User/me/my-project' }, function (err, data) {
    // do something with the response object. 
// to only include production dependencies 
    directory: '/User/me/my-project',
    production: true
}, function (err, data) {
    // do something with the response object. 

The data returned from find() is an array of modules, each of which is represented by an object as the following example:

  "id": "example@0.2.9",
  "name": "example",
  "version": "0.2.9",
  "repository": "http:\/\/\/iandotkelly\/example",
  "directory": "\/Users\/ian\/example",
  "licenseSources": {
    "package": {
      "sources": [
          "license": "MIT",
          "url": ""
    "license": {
      "sources": [
          "filePath": "\/Users\/ian\/Personal\/example\/LICENSE",
          "text": "the text of the license file",
          "name": function() { // function that returns the name of the license if known }
    "readme": {
      "sources": [
          "filePath": "\/Users\/ian\/Personal\/example\/",
          "text": "text of the readme"
          "name": function() { // function that returns the name of the license if known }



To run the unit tests, install development dependencies and run tests with 'gulp'. Requires gulp.js to be installed globally.

# only need to install gulp if you have not done so already 
$ npm install -g gulp
cd nlf
$ npm install
$ gulp

If you contribute to the project, tests are written in mocha, using should.js or the node.js assert module.