var storage = multer.diskStorage({
destination: function(req, file, cb) {
cb(null, './uploads');
},
filename: function (req, file, cb) {
cb(null , file.originalname);
}
});

###################### OR ######################

var storage = multer.diskStorage({
destination: (req, file, callBack) => {
callBack(null, './public/images/')
},
filename: (req, file, callBack) => {
callBack(null, file.fieldname + '-' + Date.now() + path.extname(file.originalname))
}
})

limits :- You can set a limit on the size of the file that is being uploaded.
const upload = multer({
storage: storage,
limits : {fileSize : 2000000},

// limits: { fileSize: 1 * 1024 * 1024 }, // 1MB fileFilter: (req, file, cb) => {
if (file.mimetype == "image/png" || file.mimetype == "image/jpg" || file.mimetype == "image/jpeg") {
cb(null, true);
} else {
cb(null, false);
const err = new Error('Only .png, .jpg and .jpeg format allowed!')
err.name = 'ExtensionError'
return cb(err);
}
}, });
fileSize is in bytes. (2000000 bytes = 2MB)

function fileFilter (req, file, cb) {
// To reject this file pass `false`, like so:
cb(null, false);
// To accept the file pass `true`, like so:
cb(null, true);
// You can always pass an error if something goes wrong:
cb(new Error('I don\'t have a clue!'));
}

function fileFilter (req, file, cb) {
// Extensio of file Allowed
const filetypes = /jpeg|jpg|png|gif/;

// Check extension
const extname = filetypes.test(path.extname(file.originalname).toLowerCase());
// Check mimetype
const mimetype = filetypes.test(file.mimetype);

if(mimetype && extname){
return cb(null,true);
} else {
cb('Error: Only Images!');
}
}

app.post("/images_upload", upload.array("my_files", 10), (req, res) =>{
try {
res.send(req.files);
} catch (error) {
console.log(error);
res.send(400);
}
});

// Use of Multer
var storage = multer.diskStorage({
destination: (req, file, callBack) => {
callBack(null, './public/images/')
//callBack(null, path.join(__dirname, './images/'))

},
filename: (req, file, cb) => {
cb(null, file.fieldname + '-' + Date.now() + path.extname(file.originalname))
// cb(null, file.fieldname + '-' + Date.now() + file.originalname.match(/\..*$/)[0])
}
})
var upload = multer({ storage: storage }); // for single file upload
// var upload = multer({ storage : storage }).array('userPhoto',10); // for multiple file upload

// ########## multiple file upload start ###############
router.get('/upload-multiple-files', function(req,res){
res.render('upload-multiple-file', {title: 'Upload Multiple files'})
})
router.post('/upload_multiple', upload.array('resume',10), (req, res) => {
var file = req.files;
console.log(file);
if(file.length > 0 )
{
console.log("yes");
}
else{
console.log("no");
}

res.redirect('/users/upload-multiple-files');
});
// ############ multiple file upload end. ##################

router.post('/save_user', upload.single('resume'), function(req, res, next){
// router.post('/save_user', function(req, res, next){

if (!req.file) {
console.log("File not uploaded!");
}
else
{
var file_neme = req.file.filename;
// console.log(req.file.filename)
}

/* upload(req,res,function(err) {
if(err) {
// return res.end("Error uploading multiple file.");
console.log("File not uploaded!");
}
var file_neme = req.file.filename;
// res.end("multiple File is uploaded");
});
*/

})

const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, '/tmp/my-uploads')
},
filename: function (req, file, cb) {
const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1E9)
cb(null, file.fieldname + '-' + uniqueSuffix)
}
})

.single(fieldname)
Accept a single file with the name fieldname. The single file will be stored in req.file.

.array(fieldname[, maxCount])
Accept an array of files, all with the name fieldname. Optionally error out if more than maxCount files are uploaded. The array of files will be stored in req.files.

.fields(fields)
Accept a mix of files, specified by fields. An object with arrays of files will be stored in req.files.
.none()
Accept only text fields. If any file upload is made, error with code "LIMIT_UNEXPECTED_FILE" will be issued.

.any()
Accepts all files that comes over the wire. An array of files will be stored in req.files.

router.post('/upload_multiple', upload.array('resume',10), (req, res) => {
var file = req.files;
// console.log(file);
if(file.length > 0 )
{
for(i = 0; i < file.length; i++)
{
const docname = req.files[i];
console.log(docname.filename);
}

}
else{
console.log("no");
}

res.redirect('/users/upload-multiple-files');
});