Uploading multiple files with multer, but from different fields?

Question

How can I have multer accept files from multiple file type fields?

I have the following code that uploads a single file, using multer in node.js:

var storage =   multer.diskStorage({
  destination: function (req, file, callback) {
    callback(null, './public/uploads');
  },
  filename: function (req, file, callback) {
    callback(null, file.fieldname + '-' + Date.now());
  }
});

var upload = multer({ storage : storage });

app.post('/rest/upload', upload.array('video', 1), function(req, res, next){
    ...
}

From the following form, on the condition only the video field has a value (if I specify both I get an 'Unexpected field' error):

<form action="/rest/upload" method="post" enctype="multipart/form-data">
   <label>Video file: </label> <input type="file" name="video"/> 
   <label>Subtitles file: </label> <input type="file" name="subtitles"/> 
   <input type="submit"/>
</form>

It is not clear from the documentation how to approach this? Any suggestions would be appreciated. BTW I have tried the following parameter variations, without success:

app.post('/rest/upload', [upload.array('video', 1), upload.array('subtitles', 1)] ...
app.post('/rest/upload', upload.array('video', 1), upload.array('subtitles', 1), ...
app.post('/rest/upload', upload.array(['video', 'subtitles'], 1),  ...

Answer 1

If you want to upload multiple files/images from the same form, I have used the below code and it works fine. The path of the image is stored in the database; I will skip the database path and go straight to the upload function and how the fields are passed to the save function.

    const path = require('path');
    const multer = require('multer');
    const storage = multer.diskStorage({
        destination: (req, file, cb) => {
           if (file.fieldname === "profile") {
               cb(null, './uploads/profiles/')
           }
           else if (file.fieldname === "natid") {
               cb(null, './uploads/ids/');
           }
           else if (file.fieldname === "certificate") {
               cb(null, './uploads/certificates/')
           }
        },
        filename:(req,file,cb)=>{
            if (file.fieldname === "profile") {
                cb(null, file.fieldname+Date.now()+path.extname(file.originalname));
            }
          else if (file.fieldname === "natid") {
            cb(null, file.fieldname+Date.now()+path.extname(file.originalname));
          }
          else if (file.fieldname === "certificate") {
            cb(null, file.fieldname+Date.now()+path.extname(file.originalname));
          }
        }
    });
    const upload = multer({
        storage: storage,
        limits: {
            fileSize: 1024 * 1024 * 10
        },
        fileFilter: (req, file, cb) => {
            checkFileType(file, cb);
        }
    }).fields(
        [
            {
                name:'profile',
                maxCount:1
            },
            {
                name: 'natid', maxCount:1
            },
            {
                name: 'certificate', maxCount:1
            }
        ]
    );
    
    function checkFileType(file, cb) {
        if (file.fieldname === "certificate") {
            if (
                file.mimetype === 'application/pdf' ||
                file.mimetype === 'application/msword' ||
                file.mimetype === 'application/vnd.openxmlformats-officedocument.wordprocessingml.document'
              ) { // check file type to be pdf, doc, or docx
                  cb(null, true);
              } else {
                  cb(null, false); // else fails
              }
        }
        else if (file.fieldname === "natid" || file.fieldname === "profile") {
            if (
                file.mimetype === 'image/png' ||
                file.mimetype === 'image/jpg' ||
                file.mimetype === 'image/jpeg'||
                fiel.mimetype==='image/gif'
              ) { // check file type to be png, jpeg, or jpg
                cb(null, true);
              } else {
                cb(null, false); // else fails
              }
            }
        }
    //at the save function 

 upload(req, res, (err) => {
        if (err) {
            console.log(err);
        } else {
            if (req.file == "undefined") {
                console.log("No image selected!")
            } else {
                let datecreated = new Date();
                let fullnames = req.body.firstname + ' ' + req.body.lastname;
                let formatedphone = '';
                let phone = req.body.personalphone;
                if (phone.charAt(0) == '0') {
                    formatedphone = '+254' + phone.substring(1);
                } else if ((phone.charAt(0) == '+') && (phone.length > 12 || phone.length <= 15)) {
                    formatedphone = phone
                }
                let teachers = {
                    "teacherid": teacherid,
                    "schoolcode": req.body.schoolcode,
                    "fullnames": fullnames,
                    "email": req.body.email,
                    "dateofbirth": req.body.dateofbirth,
                    "nationalid": req.body.nationalid,
                    "personalphone": formatedphone,
                    "profile": req.files.profile[0].path,
                    "natid": req.files.natid[0].path,
                    "certificate":req.files.certificate[0].path
                }
                connection.query('INSERT INTO teachers SET ?', teachers, (error, results, fields) => {`enter code here`
                    if (error) {
                        res.json({
                            status: false,
                            message: 'there are some error with query'
                        })
                        console.log(error);
                    } else {console.log("Saved successfully");
}