🐛 fix the issue of can't open block menu when the cursor is located in an empty code block

Author: Zuoqiu-Yingyi

app/src/protyle/wysiwyg/keydown.ts

@@ -555,12 +555,17 @@ export const keydown = (protyle: IProtyle, editorElement: HTMLElement) => {
                 // https://github.com/siyuan-note/siyuan/issues/5185
                 if (range.startOffset === 0 && range.startContainer.nodeType === 3) {
                     const previousSibling = hasPreviousSibling(range.startContainer) as HTMLElement;
-                    if (previousSibling && previousSibling.nodeType !== 3 && previousSibling.getAttribute("data-type").indexOf("inline-math") > -1) {
+                    if (previousSibling &&
+                        previousSibling.nodeType !== 3 &&
+                        previousSibling.getAttribute("data-type")?.indexOf("inline-math") > -1
+                    ) {
                         protyle.toolbar.showRender(protyle, previousSibling);
                         return;
                     } else if (!previousSibling &&
-                        range.startContainer.parentElement.previousSibling && range.startContainer.parentElement.previousSibling.isSameNode(range.startContainer.parentElement.previousElementSibling) &&
-                        range.startContainer.parentElement.previousElementSibling.getAttribute("data-type").indexOf("inline-math") > -1) {
+                        range.startContainer.parentElement.previousSibling &&
+                        range.startContainer.parentElement.previousSibling.isSameNode(range.startContainer.parentElement.previousElementSibling) &&
+                        range.startContainer.parentElement.previousElementSibling.getAttribute("data-type")?.indexOf("inline-math") > -1
+                    ) {
                         protyle.toolbar.showRender(protyle, range.startContainer.parentElement.previousElementSibling);
                         return;
                     }