validate-npm-package-license ============================ Give me a string and I'll tell you if it's a valid npm package license string. ```javascript var valid = require('validate-npm-package-license'); ``` SPDX license identifiers are valid license strings: ```javascript var assert = require('assert'); var validSPDXExpression = { validForNewPackages: true, validForOldPackages: true, spdx: true }; assert.deepEqual(valid('MIT'), validSPDXExpression); assert.deepEqual(valid('BSD-2-Clause'), validSPDXExpression); assert.deepEqual(valid('Apache-2.0'), validSPDXExpression); assert.deepEqual(valid('ISC'), validSPDXExpression); ``` The function will return a warning and suggestion for nearly-correct license identifiers: ```javascript assert.deepEqual( valid('Apache 2.0'), { validForOldPackages: false, validForNewPackages: false, warnings: [ 'license should be ' + 'a valid SPDX license expression (without "LicenseRef"), ' + '"UNLICENSED", or ' + '"SEE LICENSE IN "', 'license is similar to the valid expression "Apache-2.0"' ] } ); ``` SPDX expressions are valid, too ... ```javascript // Simple SPDX license expression for dual licensing assert.deepEqual( valid('(GPL-3.0 OR BSD-2-Clause)'), validSPDXExpression ); ``` ... except if they contain `LicenseRef`: ```javascript var warningAboutLicenseRef = { validForOldPackages: false, validForNewPackages: false, spdx: true, warnings: [ 'license should be ' + 'a valid SPDX license expression (without "LicenseRef"), ' + '"UNLICENSED", or ' + '"SEE LICENSE IN "', ] }; assert.deepEqual( valid('LicenseRef-Made-Up'), warningAboutLicenseRef ); assert.deepEqual( valid('(MIT OR LicenseRef-Made-Up)'), warningAboutLicenseRef ); ``` If you can't describe your licensing terms with standardized SPDX identifiers, put the terms in a file in the package and point users there: ```javascript assert.deepEqual( valid('SEE LICENSE IN LICENSE.txt'), { validForNewPackages: true, validForOldPackages: true, inFile: 'LICENSE.txt' } ); assert.deepEqual( valid('SEE LICENSE IN license.md'), { validForNewPackages: true, validForOldPackages: true, inFile: 'license.md' } ); ``` If there aren't any licensing terms, use `UNLICENSED`: ```javascript var unlicensed = { validForNewPackages: true, validForOldPackages: true, unlicensed: true }; assert.deepEqual(valid('UNLICENSED'), unlicensed); assert.deepEqual(valid('UNLICENCED'), unlicensed); ```