如何获取Google Fit API的userId？

const { google } = require('googleapis');
const { OAuth2Client } = require('google-auth-library');

// 替换为你的客户端ID和客户端密钥
const CLIENT_ID = 'YOUR_CLIENT_ID';
const CLIENT_SECRET = 'YOUR_CLIENT_SECRET';
const REDIRECT_URI = 'YOUR_REDIRECT_URI';

const oAuth2Client = new OAuth2Client(CLIENT_ID, CLIENT_SECRET, REDIRECT_URI);

async function getAccessToken(code) {
  const { tokens } = await oAuth2Client.getToken(code);
  oAuth2Client.setCredentials(tokens);
  return tokens.access_token;
}

async function getUserId(accessToken) {
  const fit = google.fit({ version: 'v1', auth: oAuth2Client });
  const response = await fit.users().getProfile({ userId: 'me' }).execute();
  return response.data.userId;
}

// 示例调用
const code = 'YOUR_AUTHORIZATION_CODE';
getAccessToken(code).then(accessToken => {
  return getUserId(accessToken);
}).then(userId => {
  console.log('User ID:', userId);
}).catch(err => {
  console.error('Error:', err);
});