Handling Express Errors

We’ll customize the errors that multer provides. This will give you complete control of what sort of response the client gets when their upload is rejected.

Handling Express Errors

You can handle errors from middleware function by providing a function to Express. As shown below, a new function is passed as the final argument to router.post. This function accepts error, req, res, next. This call signature lets Express know the function is designed to handle errors.

The function itself sends back a JSON response with the error message from multer.

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router.post('/users/me/avatar', upload.single('avatar'), (req,res) => {
  res.send()
}, (error, req, res, next) => {
  res.status(400).send({ error : error.message })
})