chore(client/ts): fix build errors

src/public/app/types.d.ts

@@ -95,7 +95,7 @@ declare global {
             className: string;
             separateWordSearch: boolean;
             caseSensitive: boolean;
-            done: () => void;
+            done?: () => void;
         });
         unmark(opts?: {
             done: () => void;

src/public/app/widgets/find.ts

@@ -305,7 +305,10 @@ export default class FindWidget extends NoteContextAwareWidget {
         const matchCase = this.$caseSensitiveCheckbox.prop("checked");
         const wholeWord = this.$matchWordsCheckbox.prop("checked");
 
-        const { totalFound, currentFound } = await this.handler?.performFind(searchTerm, matchCase, wholeWord);
+        if (!this.handler) {
+            return;
+        }
+        const { totalFound, currentFound } = await this.handler.performFind(searchTerm, matchCase, wholeWord);
 
         this.$totalFound.text(totalFound);
         this.$currentFound.text(currentFound);

src/public/app/widgets/find_in_code.ts

@@ -38,7 +38,7 @@ export default class FindInCode {
         // See https://codemirror.net/addon/search/searchcursor.js for tips
         const codeEditor = await this.getCodeEditor();
         if (!codeEditor) {
-            return;
+            return { totalFound: 0, currentFound: 0 };
         }
 
         const doc = codeEditor.doc;