Fix utf8 encoded strings by using a different base64 decoder

frontend/tty-receiver/base64.js

@@ -140,8 +140,17 @@ var Base64 = {
         }
 
         return string;
-    }
+    },
 
+    base64ToArrayBuffer: function (input) {
+        var binary_string =  window.atob(input);
+        var len = binary_string.length;
+        var bytes = new Uint8Array( len );
+        for (var i = 0; i < len; i++)        {
+            bytes[i] = binary_string.charCodeAt(i);
+        }
+        return bytes;
+    }
 }
 
 export default Base64;

frontend/tty-receiver/tty-receiver.ts

@@ -45,7 +45,7 @@ class TTYReceiver {
 
             if (message.Type === "Write") {
                 let writeMsg = JSON.parse(msgData)
-                this.xterminal.write(base64.decode(writeMsg.Data))
+                this.xterminal.writeUtf8(base64.base64ToArrayBuffer(writeMsg.Data));
             }
 
             if (message.Type == "WinSize") {