Image file upload with node.js

Question

I'm trying to adapt my code to upload files, but I'm not getting it, I looked in the community and I didn't understand, I'm still new to this. It always falls on the error json return, do you know what it can be? File where you have the logic

async img(request, response){
    multer({
        storage: multer.diskStorage({
            destination: (req, file, cb) => {
                cb(null, "./Uploads")
        },
        filename: (req, file, cb) => {

            cb(null, Date.now().toString() + '-' + file.originalname)

        },
        fileFilter: (req, file, cb) => {
            const extensionImg = ['image/png', 'image/jpg', 'image/jpeg'].find
            (formatPermitted => formatPermitted == file.mimetype)

            if(extensionImg){
                return cb(null, true)
            }
                return cb(null, false)
            } 

       })

    }).single('image')

    if(request.file){
        return response.status(200).json({erro: false, message: "ok"});
    }else{
        return response.status(400).json({erro: true, message: "error"});
    }
} 

File where the route is

const IncidentsController = require('./controllers/IncidentsController');

const routes = express.Router();

routes.post('/uploads', IncidentsController.img)

Answer 1

multer(...).single(...) returns a middleware function. That middleware function that it returns has to be actually called in order to do something.

Typically, you would define the middleware outside a request handler and then use it as middleware on one or more request handlers.

 const imgMulterMiddleware = multer({
    storage: multer.diskStorage({
        destination: (req, file, cb) => {
            cb(null, "./Uploads")
    },
    filename: (req, file, cb) => {

        cb(null, Date.now().toString() + '-' + file.originalname)

    },
    fileFilter: (req, file, cb) => {
        const extensionImg = ['image/png', 'image/jpg', 'image/jpeg'].find
        (formatPermitted => formatPermitted == file.mimetype)

        if(extensionImg){
            return cb(null, true)
        }
            return cb(null, false)
        } 

   })

}).single('image');

Then, use that middleware as needed:

routes.post('/uploads', imgMulterMiddleware, (req, res) => {
     // do something with req.file here which will be set
     // by the middleware if it was successful

    if (req.file) {
        res.json({erro: false, message: "ok"});
    } else {
        res.status(400).json({erro: true, message: "error"});
    }
});