new FieldTypes.Url({ 
    allowed_origins: ["https://www.youtube.com"], // will accept only youtube links
    allowed_protocols: ["https"] // will accept only https links
})

const app = new (class extends App {
    config = {
        /*...*/
    };
    manifest = {
        /*...*/
    };
    collections = {
        ...App.BaseCollections,
        url: new (class extends Collection {
		fields = {
			url: new FieldTypes.Url(params),
		};
	})()
    };
})();