Check if you are sending all the files with the same name "files".

You can try to change this:

upload.array('files')

to this:

upload.any()

any() method will accept all the files. It will not check the name of the field.

Also, after this change, you have to change this line:

 var paths = req.files.map(files => file.path);

You have an error there, because you are mapping files and you are accessing file. Change it like this:

const paths = req.files.map(file => file.path);

Check this is the complete working code.

 const express = require('express')
    const app = express()
    const port = 3000
    const multer  = require('multer')
    const upload = multer({ dest: 'uploads/' })
    
    
    app.get('/', (req, res) => {
        res.send('<form id="form_el" class=\'new-project\' action=\'/MOCReport\' method=\'POST\' enctype="multipart/form-data">\n' +
            '    <label for=\'file\'>Select your image:</label>\n' +
            '    <input type=\'file\' multiple=\'multiple\' accept=\'image/!*\' name=\'uploadedImages\' id=\'file\' />\n' +
            '    <span class=\'hint\'>Supported files: jpg, jpeg, png.</span>\n' +
            '    <button type=\'submit\'>upload</button>\n' +
            '</form>')
    })
    
    
    app.post('/MOCReport',upload.any(),function (req, res, next){
        const files = req.files;
        console.log(JSON.stringify(files));
    
        res.send('Uploaded successfully');
    });
    
    app.listen(port, () => {
        console.log(`Example app listening on port ${port}`)
    })

I also had a similar problem

Please review the react code

Please check the structure to see if the file information is properly loaded in formdata.