perf: Improve performance of Placeholder extension

shared/editor/extensions/Placeholder.ts

@@ -22,14 +22,12 @@ export default class Placeholder extends Extension {
             const { doc } = state;
             const decorations: Decoration[] = [];
             const completelyEmpty =
-              doc.textContent === "" &&
               doc.childCount <= 1 &&
-              doc.content.size <= 2;
+              doc.content.size <= 2 &&
+              doc.textContent === "";
 
+            if (completelyEmpty) {
               doc.descendants((node, pos) => {
-              if (!completelyEmpty) {
-                return;
-              }
                 if (pos !== 0 || node.type.name !== "paragraph") {
                   return;
                 }
@@ -40,6 +38,7 @@ export default class Placeholder extends Extension {
                 });
                 decorations.push(decoration);
               });
+            }
 
             return DecorationSet.create(doc, decorations);
           },