Cannot return method using module exports

Question

I am trying to make a database file that delivers connection, model etc for mongoose (MongoDb).

So when I return the Mongoose Model, the create method becomes "undefined".

database.js

//model connection 
exports.MongoModel = async function ({connectionName, collection, schema}){
    //get connection data 
    const databaseData = connectionsArray[connectionName];

    //create url 
    const mongoUrl = `${dbUrl}${databaseData.databaseName}`;

    //connection 
    const connection = Mongoose.createConnection(mongoUrl, databaseData.options);

    //model with schema
    const Model = connection.model('files',schema);

    console.log(Model.create);// displays [Function: create] in console

    //return model
    return Model
}//MongoModel ends

When imported to the other file

FileUploads.js

const { MongoModel } = require('@src/config/database');


const FilesModel = MongoModel({connectionName:'files', collection: 'files', schema: FilesSchema});

console.log(FilesModel); // Displays Promise { Model { files } }
console.log(FilesModel.create); // Displays undefined

Note: I am very new to this platform so please pardon me typo's.

score 0 · Answer 1 · answered Jun 15 '20 at 07:42

Well try it like this:

//model connection 
function MongoModel({connectionName, collection, schema}){
    //get connection data 
    const databaseData = connectionsArray[connectionName];

    //create url 
    const mongoUrl = `${dbUrl}${databaseData.databaseName}`;

    //connection 
    const connection = Mongoose.createConnection(mongoUrl, databaseData.options);

    //model with schema
    const Model = connection.model('files',schema);

    console.log(Model.create);// displays [Function: create] in console

    //return model
    return Model
}//MongoModel ends 

module.exports = { MongoModel }

You need to export an Object with your MongoModel in it. Now you should be able to destructure it at the import statement.

And i dont see a reason to use async here

Iyanu Adelekan · Accepted Answer · 2020-06-15T08:19:37.843

0

In your code 'MongoModel' references an async function which always returns a Promise. That is why you see Promise { Model { files } } when you log the object to your console. Two things you can do are:

Option 1: Remove the 'async' key word from your function declaration. This way your function returns your model object instead of a promise. Option 2: Add a callback to get the data returned by the promise as shown below:

MongoModel({connectionName:'files', collection: 'files', schema: FilesSchema})
    .then((FileModel) => {
         console.log(FileModel.create); // should display [Function: create]
});

edited Jun 15 '20 at 08:19

answered Jun 15 '20 at 08:07

Iyanu Adelekan

396
2
7

Going from an async function to a callback-based one doesn't sound like a good move. – AKX Jun 15 '20 at 08:12
I wasn't recommending a particular approach. I was just making him aware of two options he could take to resolve this issue. – Iyanu Adelekan Jun 15 '20 at 08:24
Thanks, @IyanuAdelekan for the answer. I have remove async as it was not necessary for the method. – Pratik Patel Jun 15 '20 at 10:29

Cannot return method using module exports

2 Answers2