added utf-16-base64 example

javascript/encoding/utf-16-base64.js

@@ -0,0 +1,41 @@
+/**
+ * Base 64 encodes UTF-16 encoded strings
+ *
+ * @param {*} string
+ * @return {*}
+ */
+function btoaUTF16(string) {
+  const charCodeArray = new Uint16Array(string.length);
+
+  // you could use a for loop without the split to move in the string for better performance
+  string.split("").forEach((_, index) => {
+    charCodeArray[index] = string.charCodeAt(index);
+  });
+
+  return btoa(String.fromCharCode(...new Uint16Array(charCodeArray.buffer)));
+}
+
+/**
+ * Decodes base64 encoded UTF-16 strings
+ *
+ * @param {*} encoded
+ * @return {*}
+ */
+function atobUTF16(encoded) {
+  binary = atob(encoded);
+  const bytes = new Uint16Array(binary.length);
+
+  // you could use a for loop without the split to move in the string for better performance
+  binary.split("").forEach((_, index) => {
+    bytes[index] = binary.charCodeAt(index);
+  });
+
+  return String.fromCharCode(...new Uint16Array(bytes.buffer));
+}
+
+// Our base64 string with weird chars
+const encoded = btoaUTF16("HUË - Sársziget");
+const decoded = atobUTF16(encoded);
+
+console.log("encoded:", encoded);
+console.log("decoded:", decoded);