Allow keyboard shortcut hotkeys to be modifiers only (#916)

* Allow hotkeys to be modifiers only

* Include meta keycodes

1 files changed, 7 insertions, 4 deletions

diff --git a/ext/js/input/hotkey-handler.js b/ext/js/input/hotkey-handler.js
index 0f11fe87..cb95b805 100644
--- a/ext/js/input/hotkey-handler.js
+++ b/ext/js/input/hotkey-handler.js
@@ -32,7 +32,7 @@ export class HotkeyHandler extends EventDispatcher {
         super();
         /** @type {Map<string, (argument: unknown) => (boolean|void)>} */
         this._actions = new Map();
-        /** @type {Map<string, import('hotkey-handler').HotkeyHandlers>} */
+        /** @type {Map<(string | null), import('hotkey-handler').HotkeyHandlers>} */
         this._hotkeys = new Map();
         /** @type {Map<import('settings').InputsHotkeyScope, import('settings').InputsHotkeyOptions[]>} */
         this._hotkeyRegistrations = new Map();
@@ -171,7 +171,11 @@ export class HotkeyHandler extends EventDispatcher {
      * @param {KeyboardEvent} event
      */
     _onKeyDown(event) {
-        const hotkeyInfo = this._hotkeys.get(event.code);
+        let hotkeyInfo = this._hotkeys.get(event.code);
+        const modifierKeycodes = ['ControlLeft', 'ControlRight', 'ShiftLeft', 'ShiftRight', 'AltLeft', 'AltRight', 'MetaLeft', 'MetaRight'];
+        if (modifierKeycodes.includes(event.code)) {
+            hotkeyInfo = this._hotkeys.get(null); // Hotkeys with only modifiers are stored as null
+        }
         if (typeof hotkeyInfo !== 'undefined') {
             const eventModifiers = getActiveModifiers(event);
             if (this._invokeHandlers(eventModifiers, hotkeyInfo, event.key)) {
@@ -228,8 +232,7 @@ export class HotkeyHandler extends EventDispatcher {
         this._hotkeys.clear();
         for (const [scope, registrations] of this._hotkeyRegistrations.entries()) {
             for (const {action, argument, key, modifiers, scopes, enabled} of registrations) {
-                if (!(enabled && key !== null && action !== '' && scopes.includes(scope))) { continue; }
-
+                if (!(enabled && (key !== null || modifiers !== null) && action !== '' && scopes.includes(scope))) { continue; }
                 let hotkeyInfo = this._hotkeys.get(key);
                 if (typeof hotkeyInfo === 'undefined') {
                     hotkeyInfo = {handlers: []};