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 <filename>"',
'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-only 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);