How to pass response back up MVC when receiving undefined-CodePudding

I'm trying to pass something down from app to controller and then model and then pass it back up, I'm moving down the chain fine into models and getting what I want to send back up, but then my controller is returning undefined. I'm aware I'm not returning the promise properly but can't quite see why I'm not returning.

Controller.js

const { fetchOwnerById } = require('./models')

const handleGreeting = (request, response) => {
    response.status(200).send({ message : 'hello from my api'})
}

const getOwnerById = (request, response) => {
    const ownerId = request.params['id'];
        fetchOwnerById(ownerId)
        .then((owner) => {
            console.log(owner)
            response.status(200).send({owner : owner})
        })
    }


module.exports = { handleGreeting, getOwnerById }

models.js

const fs = require('fs/promises')

const fetchOwnerById = (ownerId) => {
    console.log(ownerId)
    fs.readFile(__dirname   `/data/owners/${ownerId}.json`, 'utf-8').then((data) => {
        console.log(data)
        return data
        // response.status(200).send(data)
        })
}

module.exports = { fetchOwnerById }

I'm receiving TypeError: Cannot read properties of undefined (reading 'then')

CodePudding user response：

The fetchOwnerById method doesn't return anything, so it returns undefined, you need to return a promise of data so you can call then.

const fs = require('fs/promises')

const fetchOwnerById = async (ownerId) => {
    console.log(ownerId)
    return await fs.readFile(__dirname   `/data/owners/${ownerId}.json`, 'utf-8')
}

module.exports = { fetchOwnerById }