fix(frontend): mobx 6.7.0 typing

Also bumps some dependencies and updates tsconfig.json

The added workarounds should be remove once
https://github.com/mobxjs/mobx/issues/3582 is resolved.

1 files changed, 3 insertions, 2 deletions

diff --git a/subprojects/frontend/src/editor/scrollbarViewPlugin.ts b/subprojects/frontend/src/editor/scrollbarViewPlugin.ts
index c95e581d..0edaeb70 100644
--- a/subprojects/frontend/src/editor/scrollbarViewPlugin.ts
+++ b/subprojects/frontend/src/editor/scrollbarViewPlugin.ts
@@ -128,10 +128,11 @@ export default function scrollbarViewPlugin(
           Math.max(1, endLine - startLine) * lineHeight,
         );
 
-        let annotation: HTMLDivElement;
+        let annotation: HTMLDivElement | undefined;
         if (i < annotations.length) {
           annotation = annotations[i];
-        } else {
+        }
+        if (annotation === undefined) {
           annotation = ownerDocument.createElement('div');
           annotations.push(annotation);
           holder.appendChild(annotation);