TypeError: res.status is not a function

Question

I'm making a function that permits me to upload a picture to imgur in my express api (nodejs), i'm encoutering an error when calling a function returning a promise:

TypeError: res.status is not a function at uploadpicture.then

This is my code: Where error is raised:

  router.post('/upload', (req, res, next)=> { 
    var busboy = new Busboy({headers: req.headers});
    busboy.on('file', function(fieldname, file, filename, encoding, mimetype) {
        if(fieldname == 'image') {
            // the buffer
            file.fileRead = [];
            file.on('data', function(data) {
                // add to the buffer as data comes in
                this.fileRead.push(data);
            });

            file.on('end', function() {
                // create a new stream with our buffered data
                var finalBuffer = Buffer.concat(this.fileRead);
                upload = uploadpicture(finalBuffer).then((res)=>{ //success request
                  console.log(res);
                  res.status(200).json({success: true, message: "Successfully uploaded !", url: res.data.link});
                },(err)=>{ //error
                  res.status(500).json({success: false, message: "Error happenned while uploading !"});
                }).catch((error)=>{
                  console.log(error);
                  res.status(500).json({success: false, message: "Error happenned while uploading !"});
                });

            })
        }
    });
    busboy.on('finish', function() {
        //busboy finished
    });
    req.pipe(busboy);
});

And the function :

function uploadpicture(stream){ //get picture stream
    return new Promise((resolve, reject)=>{
    var options = {
      uri: 'https://api.imgur.com/3/image',
      method: 'POST',
      headers: {
          //'Authorization': 'Client-ID ' + config.client_id_imgur // put client id here
      },
      formData: {
          image: stream,
          type: 'file'
      },
      auth: {
        bearer: config.access_token_imgur,
      }
  };

  request(options)
      .then((parsedBody)=> {
          resolve(parsedBody);
      })
      .catch((err)=> {
        console.log(err);
        reject(err.toString())
      });
    });
  }

The code works perfectly, but i don't know why suddendly this error happened, i tried to :

change arrow functions to function(){} Add next to the route parameters

Nothing worked, Thanks for your help

Answer 1

At this point:

upload = uploadpicture(finalBuffer).then((res)=>{ //success request

the resis the result of promise uploadpicture function (that is the parsedBody), not the res from the express route. So indeed, it has no status function. Try change the then callback name like:

upload = uploadpicture(finalBuffer).then((otherName)=>{ //success request

Answer 2

The accepted answer directly addresses the OP's problem, but I post another solution since you can also encounter this error in other places.

When you have:

api.use((error: ErrorRequestHandler, request: ExpressRequest, response: ExpressResponse) => {
  response.status(500).end() // response.status is not a function
})

Because the error handling route must accept 4 arguments for express to identify it as an error middleware.

api.use((error: ErrorRequestHandler, request: ExpressRequest, response: ExpressResponse, next: NextFunction) => {
  response.status(500).end()
})

Just adding the next function (or whatever argument you're missing) will fix it.

https://github.com/visionmedia/supertest/issues/416#issuecomment-514508137

Answer 3

You are getting this error:

TypeError: res.status is not a function

Because the order should be (err, res, req, next) not (req, res, err, next), example below

const errorHandler = (err, req, res, next) => {
    const statusCode = res.statusCode === 200 ? 500 : res.statusCode;
    res.status(statusCode)
    res.json({
        message : err.message,
        stack :process.env.NODE_ENV === 'production' ? null : err.stack, 
    })
}