improve primary button check

Author: francescospissu

arduino-ide-extension/src/browser/library/library-list-widget.ts

@@ -201,8 +201,9 @@ class MessageBoxDialog extends AbstractDialog<MessageBoxDialog.Result> {
       options.buttons || [nls.localize('vscode/issueMainService/ok', 'OK')]
     ).forEach((text, index) => {
       const button = this.createButton(text);
-      const i = options.buttons ? options.buttons?.length - 1 : 0;
-      button.classList.add(index === i ? 'main' : 'secondary');
+      const isPrimaryButton =
+        index === (options.buttons ? options.buttons?.length - 1 : 0);
+      button.classList.add(isPrimaryButton ? 'main' : 'secondary');
       this.controlPanel.appendChild(button);
       this.toDisposeOnDetach.push(
         addEventListener(button, 'click', () => {