Waiting for the focus to return from KeePassXC-desktop back to the page

Author: a2kolbasov

keepassxc-browser/content/passkeys.js

@@ -145,6 +145,36 @@
         }
     };
 
+    /**
+     * @template T
+     * @param {() => T} action
+     * @returns {Promise<T>}
+     */
+    const callOnFocus = function (action) {
+        /*
+        Some browsers (like Firefox) reject requests to original `navigator.credentials.create/get` if the page
+        is out of focus (when the user selects a passkey in KeePassXC-desktop).
+
+        `document.visibilityState` is not suitable: if the page is visible, but the focus is on another application
+        (or DevTools), the request will be rejected.
+        */
+        return new Promise((resolve) => {
+            if (document.hasFocus()) {
+                return resolve(action());
+            }
+
+            /** @param {FocusEvent} e */
+            const listener = function (e) {
+                if (!e.isTrusted) {
+                    return;
+                }
+                resolve(action());
+            };
+
+            document.addEventListener('focus', listener, { capture: true, passive: true, once: true });
+        });
+    };
+
     // Throws errors to a correct exceptions
     const throwError = function(errorCode, errorMessage) {
         if ((!errorCode && !errorMessage) || errorCode === PASSKEYS_REQUEST_CANCELED) {
@@ -205,7 +235,7 @@
                     throwError(response?.errorCode, response?.errorMessage);
                     return null;
                 }
-                return originalCredentials.create(options);
+                return callOnFocus(() => originalCredentials.create(options));
             }
 
             return createPublicKeyCredential(response.publicKey);
@@ -231,7 +261,7 @@
                     throwError(response?.errorCode, response?.errorMessage);
                     return null;
                 }
-                return originalCredentials.get(options);
+                return callOnFocus(() => originalCredentials.get(options));
             }
 
             return createPublicKeyCredential(response.publicKey);