exercicio3.js

const fs = require('fs')
const path = './'


const readdirPromise = (path) => {
    return new Promise( ( resolve, reject ) => {
        fs.readdir( path, ( err, files) => {
            if( err ) {
                console.log('ocorreu um erro')
            }else {
                console.log(files)
            } 
        })
    })
}

readdirPromise(path).then((files)=> console.log(files))

Certinho.