How do I make propper exports in nodeJS

Question

I want to get my variable containing a file path from my routes to my controller. Eg. for router:

exports.file_path = (req, res) => {
    var file_path = storage;
    return file_path;
}

Eg. for controller:

const { file_path } = require('../routes/auth');

This is one of the combinations of things to try to get my STORAGE varibale from routes.js to controller.js but I ended up being more confused than when I started. Does anyone have any ideas how to do it?

The error I get:

throw new Error(msg);
        ^

Error: Route.post() requires a callback function but got a [object Undefined]

I tried some of the solutions alredy but I can't get them to work:

Error: .post() requires callback functions but got a [object Undefined] not working Route.get() requires a callback function but got a [object Undefined]. What did I do wrong? ...

Answer 1

I just solved this error myself, and I will provide the code to show how I fixed it.

To begin, I have 3 files in play here.

• index.js (the file that calls the API)
• user-router (where the post takes place)
• user-control (where the details of the post are defined)

The error was raised from this file, particularly line 5, where I am importing the router.

//index.js
const express = require("express");
const cors = require("cors");

const db = require("./db/connection");
const userRouter = require("./routes/user-router");    //PROBLEMATIC LINE

const app = express();
const apiPort = 3000;

app.use(express.urlencoded({ extended: true }));
app.use(cors());
app.use(express.json());

db.on("error", console.error.bind(console, "MongoDB connection error:"));

app.get("/", (req, res) => {
  res.send("Hello World!");
});

app.use("/api", userRouter);

Clearly, the post function is what is throwing the error. However, after reading through this Stack Overflow thread, I learned that the problem has to do with the connections between the files - the imports and exports of functions. This led me to look in the control folder.

//user-router.js
const express = require("express");

const UserCtrl = require("../control/user-control");     //PROBLEMATIC LINE (2)

const router = express.Router();

router.post("/user", UserCtrl.createUser);               //PROBLEMATIC LINE(1) 

module.exports = router;

What I found was that the module.exports line was the issue. What I needed to do was wrap the export in curly braces and the problem went away.

//user-controller.js
const User = require("../models/user-model");

createUser = async (req, res) => {
  //...
};

//module.exports = createUser;               //PROBLEMATIC LINE
module.exports = { createUser };             //This fixed the problem

I hope that by showing you the entire breakdown of my problem, you are able to solve yours. Also, I hope that by using my limited knowledge to try to answer a question, I can build up a few reputation points, so that I am able to respond to comments and such, LOL. Let me know if this was able to help you.

Answer 2

Don't destructure the callback function that you export:

const file_path_cb = require('../routes/auth');