How to attach file to an email with nodemailer

Include in the var mailOption the key attachments, as follow:

var mailOptions = {
...
attachments: [
    {   // utf-8 string as an attachment
        filename: 'text1.txt',
        content: 'hello world!'
    },
    {   // binary buffer as an attachment
        filename: 'text2.txt',
        content: new Buffer('hello world!','utf-8')
    },
    {   // file on disk as an attachment
        filename: 'text3.txt',
        path: '/path/to/file.txt' // stream this file
    },
    {   // filename and content type is derived from path
        path: '/path/to/file.txt'
    },
    {   // stream as an attachment
        filename: 'text4.txt',
        content: fs.createReadStream('file.txt')
    },
    {   // define custom content type for the attachment
        filename: 'text.bin',
        content: 'hello world!',
        contentType: 'text/plain'
    },
    {   // use URL as an attachment
        filename: 'license.txt',
        path: 'https://raw.github.com/andris9/Nodemailer/master/LICENSE'
    },
    {   // encoded string as an attachment
        filename: 'text1.txt',
        content: 'aGVsbG8gd29ybGQh',
        encoding: 'base64'
    },
    {   // data uri as an attachment
        path: 'data:text/plain;base64,aGVsbG8gd29ybGQ='
    }
 ]}

Choose the option that adjust to your needs.

Link:Nodemailer Repository GitHub

Good Luck!!