This is a JavaScript library to create and manipulate Research Object Crate.
Install the library:
npm install ro-crate
Note: The minimum Node.js version is 20.
Import the ROCrate class and create a new empty crate with default configurations:
const {ROCrate} = require('ro-crate');
const crate = new ROCrate();
The ROCrate constructor accepts two optional arguments:
const fs = require('fs');
// load existing metadata
const data = JSON.parse(fs.readFileSync('ro-crate-metadata.json', 'utf8'));
// create a crate using the existing data and
// configure the crate to return a property of an Entity as an array and resolve linked entity as nested object
const crate = new ROCrate(data, { array: true, link: true });
To add an Entity to the crate:
// A license
const license = {
'@id': 'https://creativecommons.org/licenses/by/4.0/',
'@type': 'CreativeWork',
'description': 'Attribution 4.0 International (CC BY 4.0) ...',
'name': 'CC BY 4.0'
};
// add the license as an unconnected Entity
crate.addEntity(license);
// add the license to the root dataset
crate.rootDataset.license = {'@id': license['@id']};
// or alternatively, add a new entity directly into a property of other entity :
crate.rootDataset.license = license;
Use an entity just like a normal object:
let lic = create.getEntity(license['@id']);
console.log(lic.name); // prints 'CC BY 4.0';
// set a property directly
lic.name = 'CC BY 4.0 dummy';
// or with the setProperty method
crate.setProperty(license['@id'], 'name', 'CC BY 4.0 dummy');
console.log(lic.name); // prints 'CC BY 4.0 dummy';
Modifying an array of values in the property is not supported yet:
lic.test = [1,2,3];
lic.test.push(4); // this does not work
console.log(lic.test); // prints '[1,2,3]';
// use this instead
lic.test = lic.test.concat(4);
// or this
crate.addValues(license['@id'], 'test', 4);
Root Dataset is a special entity that is mandated by the standard:
const rootDataset = crate.rootDataset;
rootDataset.name = 'Tutorial Crate';
rootDataset.description = 'This is an example crate for educational purposes.'
const today = new Date().toISOString().split('T')[0]
rootDataset.datePublished = today;
The value of the returned property can be set to be always as an array:
const crate1 = new ROCrate();
const crate2 = new ROCrate({array: true});
crate1.rootDataset.name = 'Tutorial Crate';
crate1.rootDataset.test = ['test1', 'test2'];
crate2.rootDataset.name = 'Tutorial Crate';
crate2.rootDataset.test = ['test1', 'test2'];
console.log(crate1.rootDataset.name); // return 'Tutorial Crate'
console.log(crate1.rootDataset.name); // return ['test1', 'test2']
console.log(crate2.rootDataset.name); // return ['Tutorial Crate']
console.log(crate2.rootDataset.name); // return ['test1', 'test2']
Linked entities can be automatically resolved as nested objects:
const crate1 = new ROCrate();
const crate2 = new ROCrate({link: true});
const crate3 = new ROCrate({link: true, array: true});
crate1.rootDataset.license = license;
crate2.rootDataset.license = license;
crate3.rootDataset.license = license;
console.log(crate1.rootDataset.license.name); // return undefined
console.log(crate1.rootDataset.license); // return {'@id': 'https://creativecommons.org/licenses/by/4.0/'}
console.log(crate2.rootDataset.license.name); // return 'CC BY 4.0'
console.log(crate3.rootDataset.license.name); // return undefined, property license is a array
console.log(crate3.rootDataset.license[0].name); // return 'CC BY 4.0'
To save the rocrate data to a file, use JSON.stringify:
// Write pretty-printed JSONLD into the directory
fs.writeFileSync('ro-crate-metadata.json', JSON.stringify(crate, null, 2));
For more usage examples, see the test files under the test directory.
For more details, refer to the full API documentation.
Use the RO-Crate-HTML to generate a HTML preview from the RO-Crate Metadata File ro-crate-metadata.json.
There is a script included with this library that can check crates.
Check a crate:
roccheck /path/to/crate/directory
This is produce a simple report.