f0818.js

const createInfo = (start, max) => {
    const threads = GmailApp.getInboxThreads(start, max)
    const matrix = threads.map(v => (
        [
            v.getId(),
            v.getFirstMessageSubject(),
            v.getMessageCount()
        ]
    ))
    return matrix
}

const createSpread = (matrix, filename = 'default') => {
    const ss = SpreadsheetApp.create(filename)
    const range = ss.getActiveSheet()
        .getRange(...[1, 1], matrix.length, matrix[0].length)
    range.setValues(matrix)
    return ss.getId()
}
const sendMail = (recipient, subject, matrix) => {
    const body = matrix.map(v => v.join(' ')).join('\n')
    GmailApp.sendEmail(recipient, subject, body)
}
const main = () => {
    const matrix = createInfo(10, 3)
    // const id = createSpread(matrix, '0818')
    sendMail(
        '[email protected]',
        'mail info',
        matrix
    )
}