Merge pull request #1293 from remotestorage/rosano-patch-2

Document set global.fetch

doc/nodejs.rst

@@ -5,6 +5,12 @@ Although remoteStorage.js was initially written for being used in browsers, we
 do support using it in a Node.js environment as well. See :doc:`this section
 </getting-started>` for getting started.
 
+.. HINT::
+   Node 18 includes ``fetch`` natively, but earlier versions do not, and so it
+   may be necessary to set ``global.fetch`` with a polyfill such as `node-fetch`_.
+
+.. _node-fetch: https://www.npmjs.com/package/node-fetch
+
 The main difference between rs.js in a browser and using it on a server or in a
 CLI program is how to connect a storage. The RS protocol uses the OAuth
 Implicit Grant flow for clients to receive a bearer token, which they can use