use prettier for typescript

helix/settings.nix

@@ -25,12 +25,19 @@
     languages.language = [
       {
         name = "html";
-        language-server = {command = "html-languageserver"; };
+        language-server = { command = "html-languageserver"; };
         formatter = {
           command = "prettier";
           args = [ "--parser" "html" ];
         };
       }
+      {
+        name = "typescript";
+        formatter = {
+          command = "prettier";
+          args = [ "--parser" "typescript" ];
+        };
+      }
       {
         name = "scss";
         language-server = { command = "vscode-css-language-server"; };