Multer unexpected field error handling - node.js

Question

The route with my multer middleware goes something like this.
router.post('my-route-path', multer.single('file'), controllerFunc)
The multer function I have defined is to allow a single file uploaded to the file system. Everything works fine, the issue is if I have define the field name to be file If in my client request I set the field name to be file it works great. But if I give it xyz then it throws an error. Which it should the problem is I can't seem to catch that error, in my catch(e) block of my promise.
This is the error I get
Error: Unexpected field
at makeError (F:\Servup\chat\node_modules\multer\lib\make-error.js:12:13)
at wrappedFileFilter (F:\Servup\chat\node_modules\multer\index.js:40:19)
at Busboy.<anonymous> (F:\Servup\chat\node_modules\multer\lib\make-middleware.js:114:7)
at emitMany (events.js:146:13)
at Busboy.emit (events.js:223:7)
at Busboy.emit (F:\Servup\chat\node_modules\busboy\lib\main.js:38:33)
at PartStream.<anonymous> (F:\Servup\chat\node_modules\busboy\lib\types\multipart.js:213:13)
at emitOne (events.js:115:13)
at PartStream.emit (events.js:210:7)
at HeaderParser.<anonymous> (F:\Servup\chat\node_modules\dicer\lib\Dicer.js:51:16)
at emitOne (events.js:115:13)
at HeaderParser.emit (events.js:210:7)
at HeaderParser._finish (F:\Servup\chat\node_modules\dicer\lib\HeaderParser.js:68:8)
at SBMH.<anonymous> (F:\Servup\chat\node_modules\dicer\lib\HeaderParser.js:40:12)
at emitOne (events.js:115:13)
at SBMH.emit (events.js:210:7)
The current implementation that I tried in my catch block was this. (this doesn't work)
catch(e => {
if (e === 'Unexpected field') {
// catch that error here
}
});

Answer 1

You can catch an unexpected field error by doing this
url: https://www.npmjs.com/package/multer
var upload = multer().single('avatar')
app.post('/profile', function (req, res) {
upload(req, res, function (err) {
if (err) {
// An error occurred when uploading
return
}
// Everything went fine
})
})