How to print the console response to postman or browser? - node.js

Question

Okay I am trying on gmail API ? It is driving me crazy, I am kind of new too it. First of all I want to print JSON response of Email and Labels to Browser or postman. Second Everytime I call API i have to reauthenticate.
any help would be really appreacited. what can I do in order to get to print response in browser which I am getting in console.
const { google } = require('googleapis');
const express = require('express');
const OAuth2Data = require('./credentials.json');
const fs = require('fs');
const { response } = require('express');
const app = express()
const TOKEN_PATH = 'token.json';
const CLIENT_ID = OAuth2Data.client.id;
const CLIENT_SECRET = OAuth2Data.client.secret;
const REDIRECT_URL = OAuth2Data.client.redirect_uris;
const oAuth2Client = new google.auth.OAuth2(CLIENT_ID, CLIENT_SECRET, REDIRECT_URL)
var authed = false;
app.get('/', (req, res) => {
if (!authed) {
// Generate an OAuth URL and redirect there
const url = oAuth2Client.generateAuthUrl({
access_type: 'offline',
scope: 'https://mail.google.com/'
});
console.log(url)
res.redirect(url);
} else {
const gmail = google.gmail({ version: 'v1', auth: oAuth2Client });
gmail.users.labels.list({
userId: 'me',
}, (err, res) => {
if (err) return console.log('The API returned an error: ' + err);
const labels = res.data.labels;
if (labels.length) {
console.log('Labels:');
labels.forEach((label) => {
console.log(`- ${label.name}`);
});
} else {
console.log('No labels found.');
}
});
res.send('Logged in')
}
})
app.get('/auth/google/callback', function (req, res) {
const code = req.query.code
if (code) {
// Get an access token based on our OAuth code
oAuth2Client.getToken(code, function (err, token) {
if (err) {
console.log('Error authenticating')
console.log(err);
} else {
console.log('Successfully authenticated');
oAuth2Client.setCredentials(token);
fs.writeFile(TOKEN_PATH, JSON.stringify(token), (err) => {
if (err) return console.error(err);
console.log('Token stored to', TOKEN_PATH);
});
authed = true;
res.redirect('/')
}
});
}
});
const port = process.env.port || 5000
app.listen(port, () => console.log(`Server running at ${port}`));
app.get('/m',(req, res) => {
if (!authed) {
// Generate an OAuth URL and redirect there
const url = oAuth2Client.generateAuthUrl({
access_type: 'offline',
scope: 'https://mail.google.com/'
});
console.log(url)
res.redirect(url);
}
else {
const gmail1 = google.gmail({ version: 'v1', auth: oAuth2Client });
gmail1.users.messages.list({userId: 'me', maxResults: 2}, function (err, res) {
if (err) {
console.log('The API returned an error 1: ' + err);
return;
}
// Get the message id which we will need to retreive tha actual message next.
for (let index = 0; index < 2; index++) {
var message_id = res['data']['messages'][index]['id'];
gmail1.users.messages.get({auth:oAuth2Client, userId: 'me', 'id': message_id}, function(err, res) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
console.log('data',res['data']);
});
}
// Retreive the actual message using the message id
});
}
})