how to verify google sign in chrome extension using launchWebAuthFlow on nodejs server

Question

I want to signin using google to my server in chrome extension. So I am using launchWebAuthFlow in background.js. Here is the code

function showAuthDialog(url, sendResponse) {
  try {
    chrome.identity.launchWebAuthFlow(
      {
        url: url,
        interactive: true,
      },
      // returns promise only if authorization is successfull
      function (redirectUrl) {
        // URL will include a parameter that either is an access token or can be exchanged for an access token
        if (redirectUrl) {
          sendResponse({ data: { redirectUrl } });
        } else {
          sendResponse({ err: "Something went wrong." });
        }
      }
    );
  }
  catch (err) {
    alert("Something went wrong");
  }
}

and

showAuthDialog(identityUrl, sendResponse);
identityUrl = getGoogleAuthEndpoint();

and here is getGoogleAuthEndpoint

function getGoogleAuthEndpoint() {
  const nonce = encodeURIComponent(
    Math.random().toString(36).substring(2, 15) +
    Math.random().toString(36).substring(2, 15)
  );

  const googleOpenIdEndpointUrl =
    `https://accounts.google.com/o/oauth2/v2/auth?client_id=${googleLoginInfo.clientId}` +
    `&response_type=id_token&redirect_uri=https://${config.chromeAppId}.chromiumapp.org` +
    `&state=dxchgv&scope=openid email profile&prompt=consent&nonce=${nonce}`;

  return googleOpenIdEndpointUrl;
}

now this will return redirectUrl from which i can extract the email and name

with this user I want to login/signup on my own nodejs server. So i can call my nodejs login api call with name/email but by this mean users can login with just email only and get JWT token.

Is there any other way that i can verify on my node server that this email is coming from authenticated flow?

I read on this that google will return u the code that you can verify on server and get user info on server, but with launchWebAuthFlow, I am not getting any code?

Any help? or the way to achieve the same?