make reference to global conditional

lib/checker.js

@@ -27,7 +27,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 const defaults = require('./defaults');
 const {Utils} = require('./utils');
-const fetch = global.fetch || require('cross-fetch');
+const _g = typeof window === 'object' ? window : (typeof global === 'object' ? global : {});
+const fetch = _g.fetch || require('cross-fetch');
 
 function includesTextCI(arr, texts) {
   // string entries in which one of it must exist in the array, eg ['a','b']

lib/rocrate.js

@@ -16,7 +16,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 //@ts-check
 
-const fetch = global.fetch || require('cross-fetch');
+const _g = typeof window === 'object' ? window : (typeof global === 'object' ? global : {});
+const fetch = _g.fetch || require('cross-fetch');
 const defaults = require('./defaults');
 const { Utils } = require('./utils');
 const { Node, Handler, ArrayHandler, Symbols } = require('./node');

package.json

@@ -1,6 +1,6 @@
 {
   "name": "ro-crate",
-  "version": "3.3.8",
+  "version": "3.3.9",
   "description": "Research Object Crate (RO-Crate) utilities for making and consuming crates",
   "main": "index.js",
   "scripts": {