Set the @base to current URL.

This is what an empty value technically does, but setting it in the
form data makes that clearer than hiding it in the guts of the machine.

It can be overriden via that same form field.

Author: BigBlueHat

playground/next/editor.mjs

@@ -331,7 +331,7 @@ window.app = createApp({
   outputTab: 'expanded',
   options: {
     processingMode: 'json-ld-1.1',
-    base: '',
+    base: window.location.href,
     compactArrays: true,
     compactToRelative: true,
     rdfDirection: '',