Fix crash on startup when no custom key binding had been set (ever)

docs/changelog.md

@@ -2,7 +2,11 @@
 
 Here are the most notable changes in each release. For a more detailed list of changes, see the [Github Releases page](https://github.com/heyman/heynote/releases).
 
-## 2.6.0 (not yet released)
+## 2.6.1
+
+- Fix crash when no custom key binding had been set
+
+## 2.6.0
 
 - Add setting for rendering white-space (spaces as dots and tabs as arrows)
 - Show key bindings in Command Palette

src/editor/keymap.js

@@ -209,7 +209,7 @@ function keymapFromSpec(specs, editor) {
 
 function getCombinedKeymapSpec(keymapName, userKeymap) {
     return [
-        ...userKeymap,
+        ...(userKeymap ? userKeymap : []),
         ...(keymapName === "emacs" ? [...EMACS_KEYMAP, ...DEFAULT_KEYMAP] : [...DEFAULT_NOT_EMACS_KEYMAP, ...DEFAULT_KEYMAP]),
     ]
 }