imap-readEmailsDay.js

const Imap = require('imap');
const moment = require('moment');
const fs = require('fs');

const imap = new Imap({
    user: 'ENDERECO_DE_EMAIL',
    password: 'SENHA',
    host: 'imap-mail.outlook.com', // 'imap.gmail.com'
    port: 993,
    tls: true,
    connTimeout: 500000,
    authTimeout: 500000,
    socketTimeout: 500000
});

function openInbox(cb) {
    imap.openBox('INBOX', true, cb);
}

imap.on('ready', () => {
    openInbox((err, box) => {
        if (err) throw err;

        const DATE = new Date();
        const MMM = moment(DATE).format('MMM');
        const DD = DATE.getDate();
        const YYYY = DATE.getFullYear();
        const FILTER_DATE = `${MMM} ${DD}, ${YYYY}`;

        console.log('======================================================');
        console.log(moment().format('DD-MM-YYYY hh:mm:ss'));
        console.log('LENDO E-MAILS DO DIA');
        console.log('======================================================');

        // Pesquisa e-mails da data, Ex.: Nov 28, 2017
        imap.search([['SINCE', FILTER_DATE]], (err, results) => {
            if (err) throw err;
            console.log(
                '======================================================'
            );
            console.log(`(${results.length}) E-MAILS ENCONTRADOS.`);
            const f = imap.fetch(results, { bodies: '' });

            f.on('message', (msg, seqno) => {
                msg.on('body', stream =>
                    stream.pipe(
                        fs.createWriteStream(
                            `${MMM}-${YYYY}-${DD}_${seqno}-email.txt`
                        )
                    )
                );
                msg.once('end', () => console.log(`E-MAIL ${seqno} -> LIDO.`));
            });
            f.once('error', err => console.error(`Ops Erro: ${err}`));
            f.once('end', () => imap.end());
        });
    });
});

imap.on('error', err => console.error(err));
imap.on('end', () => {
    console.log('CONEXÃO FINALIZADA');
    console.log('======================================================');
});

imap.connect();