Cannot read properties of undefined (reading 'log'), winston

I am trying to log errors in a file using winston, node js.

but it is giving the error as: Cannot read properties of undefined (reading 'log')

code: server.js

const path = require('path');
const express = require('express');
const app = express();
const http = require('http');
const server = http.createServer(app);
const sharp=require('sharp')
const logger=require('./errorLogger')


app.use(express.static(path.join(__dirname,"../public")));


app.get('/down', (req, res) => {

    outFile="output.jpg"
    sharp("../public/vidgo.jpg")
    .resize()
    .toFile(outFile,(err)=>{

        if(err) {
            console.log(err)
            logger.errorLogger.log('error',err) // line 37 mentioned in error
        }

        console.log("----")
        res.download(outFile,err=>{

            if(err) {
                console.log(err)
                logger.errorLogger.log('error',err)
            }

            console.log("down")
        })
    })
  });

server.listen(3000, () => {
  console.log('listening on *:3000');
});

errorLogger.js module

const {createLogger, transports,format} = require('winston')

const errorLogger=createLogger({
    transports:[
        new transports.File({
            filename:"errLogs",
            level:"error",
            format: format.combine(format.timestamp(),format.json())
        })
    ]
})

log and errors

Error: Input file is missing: ../public/vidgo.jpg]
E:\Novo Cabs\requestLog\nodeserver\server.js:37
            logger.errorLogger.log('error',err)
                               ^

TypeError: Cannot read properties of undefined (reading 'log')
    at Object.<anonymous> (E:\Novo Cabs\requestLog\nodeserver\server.js:37:32)

the file named 'errLogs' is created automatically

Add the

module.exports = logger;

to your errorLogger.js file.