Get the array value of a promise

Question

I'm trying to send multiple attachments with Sendgrid with a new promise as below. I want to return an array of objects but I don't understand how to do so. emailAttachments contains my 3 objects, but how can I return the array? Can you tell me what's wrong in my code?

const emailAttachments = []

return new Promise(function(resolve, reject){

    pdfList.map(item => {

        fs.readFile((item.frDoc), (err, data) => {
            if (err) {
              return { handled: false }
            }

            if (data) {
                
                emailAttachments.push({
                    content: data.toString('base64'),
                    filename: `document.pdf`,
                    type: 'application/pdf',
                    disposition: 'attachment'
                })

            }
        });
    })

    resolve(emailAttachments)
})

Answer 1

I think you need something like this:

async function getEmailAttachments(pdfList) {
    const emailAttachments = await Promise.all(pdfList.map((item) => {
        return new Promise(function (resolve, reject) {
            fs.readFile((item.frDoc), (err, data) => {
                if (err) {
                    reject({ handled: false });
                }
                if (data) {
                    resolve({
                        content: data.toString('base64'),
                        filename: `document.pdf`,
                        type: 'application/pdf',
                        disposition: 'attachment'
                    });
                }
            });
        });
    }));
    return emailAttachments;
}

[EDIT] Or using the promise version of readFile (sugestion of @derpirscher):

async function getEmailAttachments(pdfList) {
    const emailAttachments = await Promise.all(pdfList.map(async (item) => {
        const data = await fs.promises.readFile(item.frDoc);
        return {
            content: data.toString('base64'),
            filename: `document.pdf`,
            type: 'application/pdf',
            disposition: 'attachment'
        };
    }));
    return emailAttachments;
}