Add Passkeys Support

Closes gh-13305

javascript/lib/base64url.js

@@ -0,0 +1,33 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+"use strict";
+
+export default {
+  encode: function (buffer) {
+    const base64 = window.btoa(String.fromCharCode(...new Uint8Array(buffer)));
+    return base64.replace(/=/g, "").replace(/\+/g, "-").replace(/\//g, "_");
+  },
+  decode: function (base64url) {
+    const base64 = base64url.replace(/-/g, "+").replace(/_/g, "/");
+    const binStr = window.atob(base64);
+    const bin = new Uint8Array(binStr.length);
+    for (let i = 0; i < binStr.length; i++) {
+      bin[i] = binStr.charCodeAt(i);
+    }
+    return bin.buffer;
+  },
+};