chrome extension login id token

auth.js

// need to use launchWebAuthFlow in chrome extension 
// can't use gapi in extension
// https://github.com/google/google-api-javascript-client/issues/64

async function getIdTokenInfo(id_token: string) {
  const resp = await fetch(
    `https://oauth2.googleapis.com/tokeninfo?id_token=${id_token}`
  );
  return resp.json();
}

async function login() {
  const redirectURI = browser.identity.getRedirectURL();
  const { oauth2 } = browser.runtime.getManifest();
  const clientId = oauth2.client_id;

  const initState = sha256(`${Math.floor(Math.random() * 1024)}`);
  const authParams = new URLSearchParams({
    response_type: "id_token",
    client_id: clientId,
    scope: ["openid", "email"].join(" "),
    redirect_uri: redirectURI,
    state: `${initState}`,
    nonce: `${Math.floor(Math.random() * 100)}`,
  });

  // get oauth2 token
  const authURL = `https://accounts.google.com/o/oauth2/auth?${authParams.toString()}`;
  const responseUrl = await browser.identity.launchWebAuthFlow({
    url: authURL,
    interactive: true,
  });

  // get OIDC + email
  const url = new URL(responseUrl);
  const urlParams = new URLSearchParams(url.hash.slice(1));
  const params: { [k: string]: string } = {};
  urlParams.forEach((k, v) => (params[v] = k));
  const { state, id_token } = params;
  if (state !== initState) {
    console.error("state invalid");
    return {};
  }
  try {
    const { email, exp } = await getIdTokenInfo(id_token);
    const newData = { email, id_token, exp: exp * 1000 }; // change exp to ms
    return newData;
  } catch (e) {
    console.error(e);
    return {};
  }
}

async function logout() {
  await browser.identity.launchWebAuthFlow({ 
    url: 'https://accounts.google.com/logout',
    interactive: true,
  })
}