NodeJS & Gmail API - Access last 3 emails based on "To:" recipient - node.js

Question

I am currently utilising NodeJS and the Gmail API to access my gmail account and return the last email I've received which is obviously only going to be 1 email using this code: (which is a slightly modified version of the example seen here: https://www.codediesel.com/nodejs/how-to-access-gmail-using-nodejs-and-the-gmail-api/
var fs = require('fs');
var readline = require('readline');
var {google} = require('googleapis');
// If modifying these scopes, delete your previously saved credentials
// at TOKEN_DIR/gmail-nodejs.json
var SCOPES = ['https://www.googleapis.com/auth/gmail.readonly'];
// Change token directory to your system preference
var TOKEN_DIR = ('./');
var TOKEN_PATH = TOKEN_DIR + 'gmail-nodejs.json';
var gmail = google.gmail('v1');
//exports.confirmationEmailFinal;
// Load client secrets from a local file.
fs.readFile('client_secret.json', function processClientSecrets(err, content) {
if (err) {
console.log('Error loading client secret file: ' + err);
return;
}
// Authorize a client with the loaded credentials, then call the
// Gmail API.
authorize(JSON.parse(content), getRecentEmail);
});
/**
* Create an OAuth2 client with the given credentials, and then execute the
* given callback function.
*
* #param {Object} credentials The authorization client credentials.
* #param {function} callback The callback to call with the authorized client.
*/
function authorize(credentials, callback) {
var clientSecret = credentials.installed.client_secret;
var clientId = credentials.installed.client_id;
var redirectUrl = credentials.installed.redirect_uris[0];
var OAuth2 = google.auth.OAuth2;
var oauth2Client = new OAuth2(clientId, clientSecret, redirectUrl);
// Check if we have previously stored a token.
fs.readFile(TOKEN_PATH, function(err, token) {
if (err) {
getNewToken(oauth2Client, callback);
} else {
oauth2Client.credentials = JSON.parse(token);
callback(oauth2Client);
}
});
}
/**
* Get and store new token after prompting for user authorization, and then
* execute the given callback with the authorized OAuth2 client.
*
* #param {google.auth.OAuth2} oauth2Client The OAuth2 client to get token for.
* #param {getEventsCallback} callback The callback to call with the authorized
* client.
*/
function getNewToken(oauth2Client, callback) {
var authUrl = oauth2Client.generateAuthUrl({access_type: 'offline', scope: SCOPES});
console.log('Authorize this app by visiting this url: ', authUrl);
var rl = readline.createInterface({
input: process.stdin,
output: process.stdout
});
rl.question('Enter the code from that page here: ', function(code) {
rl.close();
oauth2Client.getToken(code, function(err, token) {
if (err) {
console.log('Error while trying to retrieve access token', err);
return;
}
oauth2Client.credentials = token;
storeToken(token);
callback(oauth2Client);
});
});
}
/**
* Store token to disk be used in later program executions.
*
* #param {Object} token The token to store to disk.
*/
function storeToken(token) {
try {
fs.mkdirSync(TOKEN_DIR);
} catch (err) {
if (err.code != 'EEXIST') {
throw err;
}
}
fs.writeFileSync(TOKEN_PATH, JSON.stringify(token));
console.log('Token stored to ' + TOKEN_PATH);
}
/**
* Lists the labels in the user's account.
*
* #param {google.auth.OAuth2} auth An authorized OAuth2 client.
*/
function listLabels(auth) {
gmail.users.labels.list({auth: auth, userId: 'me',}, function(err, response) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
var labels = response.data.labels;
if (labels.length == 0) {
console.log('No labels found.');
} else {
console.log('Labels:');
for (var i = 0; i < labels.length; i++) {
var label = labels[i];
console.log('%s', label.name);
}
}
});
}
/**
* Get the recent email from your Gmail account
*
* #param {google.auth.OAuth2} auth An authorized OAuth2 client.
*/
function getRecentEmail(auth) {
// Only get the recent email - 'maxResults' parameter
gmail.users.messages.list({auth: auth, userId: 'me', maxResults: 1,}, function(err, response) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
// Get the message id which we will need to retreive tha actual message next.
var message_id = response['data']['messages'][0]['id'];
// Retreive the actual message using the message id
gmail.users.messages.get({auth: auth, userId: 'me', 'id': message_id}, function(err, response) {
if (err) {
console.log('The API returned an error: ' + err);
return;
}
// Access the email body content, like this...
try {
const message_raw = response.data.payload.body.data;
data = message_raw;
buff = new Buffer.from(data, 'base64');
text = buff.toString();
console.log(text);
}
catch (err){
const message_raw = response.data.payload.parts[0].body.data;
console.log('error');
data = message_raw;
buff = new Buffer.from(data, 'base64');
text = buff.toString();
console.log(text);
}
});
});
}
Although this works perfectly fine, I am looking to find the 3 latest emails (not just 1) based on the email's "TO:" recipient which I currently have stored as the email variable.
Any help would be appreciated!

Answer 1

Have a look at here: https://developers.google.com/gmail/api/guides/filtering.
You can search or filter files using the messages.list and
threads.list methods. These methods accept the q parameter which
supports the same advanced search syntax as the Gmail web-interface.

Answer 2

Use filters via q property:
const email = 'myEmail#example.com';
gmail.users.messages.list({
auth: auth,
userId: 'me',
maxResults: 1,
q: `to:${email}`
}
Beside to:address you can use all other search/filter params, like is:unread etc.